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All Altius Lessons!

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Does a primary amine act as a nucleophile or a base?

Why?
1° amine - usually acts as a nucleophile

3° amine - usually acts as a base (because they are too stericlly hindered to act as a nucleophile)
Are amines soluble in water?

Why?
If they don't have long carbon chains then YES, they are very soluble in water due to Hydrogen Bonding
How does increased branching and molecular weight affect the MP and BP of an amine?
MP and BP increases with Increased molecular weight and decreased branching
Draw ammonia and ammonium
NH₃ = ammonia

NH₃⁺ = ammonium
How does basisity change from ammonia → 1° → 2° → 3 ° amines?
Basicity decreases from tertiary to secondary to primary to ammonia due to the electron donating effects of the R- group
Are Amines with four substituents electrophiles or nucleophiles?
Electrophiles ( as long as they have at least one hydrogen)
...
Draw the mechanisms for enamine/imine tautomerization
...
How does the synthesis of an alkyl amine work?

NH₃ + CH₃Br → ?

What is a problem with this reaction?
NH₃ + CH₃Br → NH₂CH₃ + HBr

1) ammonia acts as a nucleophile, attacking the alkyl halide via SN2 and kicking off the halide ion.
2) The halide ion acts as a base, abstroacting a hydrogen to quench the charge on the nitrogen.

Note: This reaction results in many side products because the resultant amine is still a good nucleophile and can react again.
How does Gabriel Synthesis work?

What is good about Gabriel Synthesis
Formation of a primary amine from a primary alkyl halide

Avoids the side products of alkyl amine synthesis

Steps:
1) The phthalimide ion, a reactive species with a full negative charge on the nitrogen, acts as a nucleophile, attacking the alkyl halide via SN2
2) The resulting intermediate is then hydrolyzed with aqueous base, releasing a primary amine.
...
A variation of the traditional Gabriel synthesis can be used to produce a primary amine plus the product shown below. Product B is a useful synthetic precursor and is therefore the targeted product of this synthesis rather than the primary amine. To obtain product B the Gabriel synthesis should be altered in which of the following ways?

A. Acid should be added, catalyzing an intermolecular reaction to form Product B
B. NaNH₂ should be added to the alkylated amine in pace of OH⁻
C. The primary amine must be reacted with one equivalent of benzene and two carboxylic acids
D. Hydrazine should be used in place of the standard amine in the first step
After alkylation of the phthalimide ion, hydroxide is normally added to substitute both amides at their carbonyl carbons and release the primary amine. If NH₂⁻ is used instead, a product very similar to product B is formed. An Additional intermolecular reaction then forms Product B. Answer B therefore is the best choice
What are some common reducing agents capable of reducing an amines?
LiAlH₄, NaBH₄, and H₂/pressure
What can reduce Nitro groups and what do they reduce to?
reduce to the associated primary amine via all the normal reducing agents

LiAlH₄, NaBH₄, and H₂/pressure
What can reduce Nitrile groups and what do they reduce to?
reduce to the associated primary amine via all of the normal reducing agents
What can reduce imines and what do they reduce to?
reduce to the associated primary amine via catalytic hyrogenation only (requires a heterogeneous catlyst such as H₂-nickle)
What can reduce amides and what do they reduce to?
reduce to the associated primary amine via LiALH₄ only
In the addition of amines to carbonyls, What do primary amines yeild?
imines
In the addition of amines to carbonyls, What do secondary amines yeild?
enamines
...
What is Wolf-Kishner Reduction?
1) CH₃COCH₃ + H₂N-NH₂ → imine
2) imine + KOH/∆ → CH₃CH₂CH₃

Complete reduction of an aldehyde or ketone to an alane via an imine intermediate. When you do addition of amines to carbonyls starting with hydrazine as the amine, the product is an amine-substituted imine. Subsequent addition of a hot, strong base (e.g., KOH/∆ replaces the imine with two hydrogens, yielding an alkane)
...
What is Hofmann Elimination?
Formation of an alkene via elimination of an amine.
Important because it yields the LEAST substituted alkene.
Which carbonyls always undergo nucleophilic addition?
Aldehyds and Ketones
What carbonyls always under go substitution?
Carboxylic Acids
Amides
Esters
Anhydrides
Why are alpha hydrogens on a carbonyl so important?
Hydrogens on a carbon one away from the carbonyl carbon are acidic due to resonance stabilization of the conjugate base

If there are two carbonyls separated by one carbon, hydrogens on this middle carbon are very acidic.
Are ketones and aldehydes nucleophiles or electrophiles?
Electrophiles
When their carbonyl carbon is attacked by a nucleophile
What is more acidic, the alpha hydrogen of a ketone, or the alpha hydrogen of an aldehyde?
aldehyde

Ketones have a e⁻ donating group which makes the CB less stable
Are aldehydes and ketones soluble in water?
Yes - If they dont have long alkyl chains
How does the boiling point of ketones and aldehydes compare to water and alkanes?
higer than equivalent alkanes, lower than water
..
What is Aldol Condensation?
The MCAT loves the aldol condensation! it is addressed in one way or another in almost every exam.
...
What are the mechanisms for Halogenation of an Aldehyde or Ketone?
...
...
What is the Haloform Reaction?
...
Is the boiling point for a carboxylic acid high or low and why?
Carboxylic acids form strong dimers involving two hydrogen bonds; this raises boiling point significantly
are carboxylic acids soluble in water?
whithout long alkyl chains, they are soluble in water. Surprisingly, they are also soluble in non-polar sovlents (although they are clearly polar)
...
Draw the mechanisms for a Decarboxylation reaction
...
What three reagents can produce an acid chloride from a carboxylic acid?
PCl₃
PCl₅
SOCl₂
Are esters more or less soluble in water compared to alcohols? Why?
less

They act as H-bond recipients but NOT donors
What is Saponfiication
The hydrolysis of an ester to yeild an alcohol and the salt of a carboxylic acid

Steps:
1)the hydroxide ion (NaOH) or (KOH) attacks the carbonyl and pushes the C=O electrons up onto the oxygen
2) The electrons collapse back down and kick off the -OR group
3) Either the -OR group, or hydroxide ion, abstracts the arboxylic acid hydrogen, yeilding a carboxylate iuon. This accociates with the Na⁺ or K⁺ in the solution to form "soap"
...
What is Acetoacetic Ester Synthesis?
The formation of a ketone from a B-keto ester

Steps:
1) A base abstracts the acidic alpha hydrogen, leaving a carbanion
2) The carbanion attacks an alkyl halide (R-X), resulting in addition of the -R group to the alpha carbon.
3) Hot acid during workup causes loss of the entire -COOR group.
What is a better leaving group ⁻OH or ⁻OR and why?
⁻OH because "R" is an electron donating group
List all carboxylic Acid derivatives in order of most stable to least stable
This patter is the exact opposite of the order of better leaving groups

Amide>Ester>Carboxylic Acid>Anhydride>Acid Cloride
Are amides soluble in water?
Primary and Secondary amides can hydrogen bond and are thus water soluble as long as they lack long alkyl chains. Tertiary amides cannot H-bond and are thus considered to have low water solubility
What is the Hofmann degradation?
Primary amides react in strong, basic solutions of Cl₂ or Br₂ to form primary amines. The mechanism includes decarboxylation, and thus shortens the length of the carbon chain

This reaction is important because it allows you to add an amine to a tertiary carbon. This is impossible via the "Synthesis of an Alkyl Amine" reaction discussed earlier.
What does electronegativity tell us about the relative reactivities of the carbons in a C=O vs a C=N bond?
the C=O carbon is more reactive because O is more electronative and therefore more polar (which will make hydrogen bonds easier)
Is hydrogen electron donating or withdrawing?
neither
Are alkenes electron withdrawing or donating?
weakly electron withdrawing
A 3° carbon must react via what mechanism?
SN1 or E1
What is a weaker acid, alcohols or water?
alcohols are always weaker acids due to the donating effect of the -R group
What increases basicity,

electron donating or withdrawing groups?
Electron donating groups increase basicity, while elctron withdrawing groups decrease basicity
What does the integumentary system consist of?
Includes the hair, nails, skin and the oil and sweat glands located within the skin.
What are the functions of the integumentary system?
Thermoregulation, protection, environmental sensory input, excretion, innate immunity, blood reservoir, vitamin D synthesis.
What is the epidermis made up of?
Made up of avascular, dead, keratinized cells.
What does the dermis consist of?
Contains blood vessels, hair follicles, sebaceous glands (oil), sudoriferous glands (sweat) and nerve endings. The dermis is a connective tissue.
How does the skin play a role in thermoregulation?
Blood vessels migrate closer to the surface of the skin and DILATE when heat needs to be released and migrate downward and CONSTRICT when heat needs to be retained. Blushing is the result of the dilation of superficial blood vessels.
What are three major characteristics of skeletal muscle?
They are voluntary, striated and multinucleate.
Provide a conceptual definition of:

1) Tendons
2) Ligaments
3) Agonist
4) Antagonist
5) Synergist
1) Tendons: connect muscle to bone
2) Ligaments: connect bone to bone
3) Agonist: The agonist is the muscle responsible for the movement. When the agonist contracts the antagonist stretches.
4) Antagonist: When the antagonist contracts the agonist stretches.
5) Synergist: Muscles that assist the agonist by stabilizing the origin bone or by positioning the insertion bone during the movement.
Why are the hinges formed by muscles and bones an example of a poor lever system with a mechanical disadvantage?
They act to increase the required force of a muscle contraction. A greater force than mg is required to lift a mas m. This is done in order to reduce the bulk of the body and increase the range of movement. If the muscle has a shorter lever arm, it is closer to the body, and thus creates less bulk.
Describe the anatomy of a skeletal muscle including the different subunits, sarcolemma, myofibrils, sarcomeres, and sarcoplasmic reticulum.
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A muscle group is a bundle of many fasciculi. A fasciculi is a bundle of many long, tubular cells called "muscle fibers." Around each muscle fiber si a specialized cell membrane called the "sarcolemma." Inside each muscle cell/fiber are many nuclei (multinucleate). Nearly the entire volume of each cell/fiber is filled with smaller round tubes called myofibrils. Myofibrils are small bundles of actin and myosin fibers interconnected in repeating units called sarcomeres. Small bundles of myofibrils are surrounded by portions of the muscle cell's endoplasmic reticulum, called the sarcoplasmic reticulum. It is the sarcoplasmic reticulum that sequesters Ca²⁺ away from the sarcomere prior to contraction.
Provide a conceptual definition for each of the following as they relate to the sarcomere:

1) Thick filament
2) Thin filament
3) Actin
4) Myosin
5) Myosin Heads
6) A band
7) I band
8) H zone
9) M line
10) Z line
.
1) Thick filament: made up of the protein myosin. Several long myosin molecules wrap around each other to form one thick filament.

2) Thin filament: Composed mainly of the globular protein actin.

3) Actin: Makes up the thin filaments

4) Myosin: Makes up thick filaments

5) Myosin Heads: Each myosin head crawls along the actin in a 5 stage cycle.

6) A band: The band measuring from the one end of the thick filament to the other end of the thick filament. Does not shorten.

7) I band: The band of only actin which shortens during contraction.

8) H zone: The band consisting of only thick filaments from end of one thin filament to end of another thin filament. Shortens during contraction.

9) M line: The middle of the sarcomere and is a line directly down the thick filaments.

10) Z line: Looks like a z, the line at the two ends of a sarcomere and consists of only thin filaments. Z lines come closer together during a contraction
What neurotransmitter is released at a neuromuscular junction? As an AP reaches a skeletal muscle where does the AP move? During contraction is calcium pumped into or out of the SR?
Acetylcholine. The AP spreads along the muscle cell sarcolemma and down specialized T-tubules that dive deep into the muscle cell. The T-tubules allow for a uniform contraction of the muscle by allowing the AP to spread through the muscle cell more rapidly. The AP is transferred to the SR, which suddenly beomces permeable to Ca²⁺ ions. At the end of each cycle, Ca²⁺ is actively pumped back into the SR. During contraction the SR becomes permeable to Ca²⁺ which is released into the myosin and causes troponin to pull the tropomyosin back, exposing the active site on the actin, and allowing the myosin head to bind.
Describe the sliding filament mechanism. Which position of the myosin heads is low energy and which position is high energy?
Myosin and actin work together sliding alongside each other to create the contractile force of skeletal muscle. Each myosin head crawls along the actin in a 5 stage cycle:

1) Tropomyosin covers an active site on the actin preventing the myosin head from binding. The myosin head remains cocked in a high-energy position with a phosphate and ADP group attached.

2) In the presence of Ca²⁺ ions, troponin pulls the tropomyosin back, exposing the active site, allowing the myosin head to bind to the actin.

3) The myosin head expels a phosphate and ADP and bends into a low energy position, dragging the actin along with it. This is called the power stroke because it causes the shortening of the sarcomere and the muscle contraction.

4) ATP attaches to the myosin head. This releases the myosin head from the active site, which is covered immediately by tropomyosin.

5) ATP splits to Pi and ADP causing the myosin head to cock into the high-energy position.
What happens to muscles if no ATP is present or if no Ca²⁺ is present?
If no ATP is present, the myosin heads cannot detach from actin and the muscle will be stuck in a contracted position called "rigor."

If no Ca²⁺ is present, we do NOT get rigor, but lack of contraction called "flaccidity."
What is a motor unit and how does it affect delicate movements, gross movements, and the strength of the contraction?
All of the cells/fibers in a skeletal muscle do not fire simultaneously during a contraction. Groups of muscle cells called "motor units" are innervated by a single neuron. Motor units come in all different sizes from large to small.

Delicate movements = very small motor units
Gross movements=larger motor units

The strength of a given contraction depends on the:
1) number of motor units being used
2) size of the motor units being used
3) frequency of action potentials (i.e., stimulation)
Describe the important features of skeletal muscles regarding energy storage, oxygen storage, and rate of division.
Skeletal muscles store large amounts of glycogen; they also require a lot of oxygen and thus have their own oxygen storage molecule, myoglobin. Myoglobin is basically one subunit of a hemoglobin molecule, capable of holding only one O₂. Mature (differentiated) skeletal muscles, like neurons, are in G₀ phase and do not divide.
List three major characteristics of cardiac muscle:

1) Voluntary/involuntary
2) Striated/Smooth
3) No nucleus/One nucleus/mutinucleate
Involuntary, Striated, One Nucleus
How does cardiac muscle contract?
Cardiac muscle contains sarcomeres and uses the same sliding filament mechanism as skeletal muscle.
What are some special features of cardiac muscle? Oxygen storage, spread of action potential, division.
Like skeletal muscle, cardiac muscle utilizes myoglobin. It also contains VERY large numbers of mitochondria to prevent fatigue. Cardiac muscle cells/fibers are connected by intercalated discs containing gap junctions. It is thru these junctions that the action potential passes after reaching the end of the purkinje fibers. Unlike skeletal muscle cells, cardiac cells continue dividing after differentiation.
Do heart muscle cells contract in response to innervation by a nerve?
No. The pacemaker (SA Node) is autorhythmic. Nerves are not required for the heart to beat, although they may modify the pace. Heart muscle will contract periodically in the absence of a stimulus.
List three major characteristics of smooth muscle:

1) Voluntary/involuntary
2) Striated/Smooth
3) No nucleus/One nucleus/mutinucleate
Involuntary, non-striated, one nucleus
Describe the important features of smooth muscle involving contraction.
Smooth muscle is NOT arranged in sarcomeres; however they do contain thick and thin filaments. Smooth muscle does NOT contract via the sliding filament mechanism. It also does not contain troponin. Instead, a complex cascade involving calmodulin (another calcium binding protein) causes contraction. (Not required for the MCAT).
Provide conceptual definitions for each of the following (regarding smooth muscle):

1) Single unit
2) Multi Unit
3) Dense Bodies
4) Intermediate Filaments
1) Single unit: AKA Visceral. The most common type of smooth muscle. The cells are connected by gap junctions spreading the AP from a single neuron through a large group of cells, and allowing the cells to contract as a single unit. Found in small arteries and veins, the stomach, intestines, uterus, and urinary bladder.

2) Multi Unit: Each multiunit smooth muscle fiber is attached directly to a neuron. A group of multiunit smooth muscle fibers can contract independently of other muscle fibers in the same location. Found in the large arteries, bronchioles, pili muscles attached to hair follicles, and the iris.

3) Dense Bodies and Intermediate Filaments: Smooth muscle cells contain intermediate filaments which are attached to dense bodies spread throughout the cell. The thick and thin filaments are attached to the intermediate filaments, and, when they contract, they cause the intermediate filaments to pull the dense bodies together. Upon contraction, the smooth muscle cell shrinks length-wise.
What are the major functions of bone?
Support, protection, movement, mineral storage (calcium and phosphate), energy storage (as fat in the marrow) and blood cell formation.
Name and describe the different bone cell types.
Osteocytes: mature bone cells surrounded by a mineral matrix.

Osteoclasts: bone cells that break down and resorb bone matrix, releasing the component minerals (Ca²⁺ and P) back into the blood.

Osteoblasts: immature bone cells that secrete collagen, organic compounds, and minerals forming a bone matrix around themselves. Once they are completely enclosed by matrix, they differentiate into osteocytes.
Describe the hormones that regulate bone cells. Which hormones effect which cells and in what specific ways?
Parathyroid hormone: Stimulate osteoclasts to reabsorb bone mineral, liberating calcium into blood. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone. Binding stimulates osteoblasts to increase their expression of RANKL and inhibits their expression of Osteoprotegerin(OPG). OPG binds to RANKL and blocks it from interacting with RANK, a receptor for RANKL. The binding of RANKL to RANK (facilitated by the decreased amount of OPG) stimulates these osteoclast precursors to fuse, forming new osteoclasts, which ultimately enhances bone resorption.

Calcitonin: Decrease blood calcium by inhibiting osteoclasts. The calcitonin receptor, found on osteoclasts, is a G protein-coupled receptor, which is coupled by Gs to adenylate cyclase and thereby to the generation of cAMP in target cells.
Provide conceptual definitions for each of the following:

1) Hematopoeisis
2) Red bone marrow
3) Yellow bone marrow
4) Spongy bone
5) Compact bone
.
1) Hematopoeisis: Formation of blood cellular components. All cellular blood components are derived from haematopoietic stem cells. Haematopoietic stem cells (HSCs) reside in the medulla of the bone (bone marrow) and have the unique ability to give rise to all of the different mature blood cell types. HSCs are self renewing: when they proliferate, at least some of their daughter cells remain as HSCs, so the pool of stem cells does not become depleted.

2) Red bone marrow: Site of hemopoeisis or red blood cell development.

3) Yellow bone marrow: Contains adipose cells for fat storage.

4) Spongy bone: Contains red bone marrow. Located at the ends of long bones.

5) Compact bone: Surrounds the medullary cavity which holds yellow bone marrow. Cortical bone facilitates bone's main functions: to support the whole body, protect organs, provide levers for movement, and store and release chemical elements, mainly calcium. As its name implies, cortical bone forms the cortex, or outer shell, of most bones.
Describe the anatomy of a long bone.
Two epiphysese (bulbous ends) cushioned by cartilage; the ends are filled with spongy bone and the shaft in between is made of compact bone; the center is a hollow cavity filled with yellow bone marrow.
What is Hydroxyapetite?
A compound of Calcium, Phosphate, and Hydroxate. It is the mineral matrix responsible for a bone's strength and is the form in which most all of the body's calcium is stored.
What is cartilage? Where is it found? Describe its perfusion.
A connective tissue made of collagen.

No perfusion or innervation.

Found in appendages such as the nose and ears, at the ends of long bones, between vertebrae, and the ribs-sternum (sternocostal) joints, etc.
What are the three different kinds of joints?
1) Fibrous (skull bones)
2) Cartilaginous (ribs to sternum)
3) Synovial (knee, elbow, etc.)
List the function and anatomy of each of the following:

1) Penis
2) Testicles
3) Scrotum
4) Seminiferous Tubules
5) Epididymis
6) Vas Deferens
7) Seminal Vesicles
8) Prostate Gland
9) Bulbourethral gland
.
1) Penis:

2) Testicles: The primary functions of the testes are to produce sperm (spermatogenesis) and to produce androgens, primarily testosterone. The presence of both testosterone and follicle-stimulating hormone (FSH) is needed to support spermatogenesis. Contains very fine coiled tubes called seminiferous tubules.

3) Scrotum: : Keep the temperature of the testes slightly lower than that of the rest of the body. The temperature is controlled by the scrotum moving the testicles closer to the abdomen when the ambient temperature is cold, and further away when it is hot.

4) Seminiferous Tubules: located in the testes, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa.

5) Epididymis: Sperm acquires motility, mature, and are stored. Tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens. During ejaculation, sperm flow from the lower portion of the epididymis (which functions as a storage reservoir). They have not been activated by products from the prostate gland, and they are unable to swim, but are transported via the peristaltic action of muscle layers within the vas deferens, and are mixed with the diluting fluids of the seminal vesicles and other accessory glands prior to ejaculation (forming semen).

6) Vas Deferens: Transport sperm from the epididymis in anticipation of ejaculation. During ejaculation the smooth muscle in the walls of the vas deferens contracts reflexively, thus propelling the sperm forward. This is also known as peristalsis.

7) Seminal Vesicles: The seminal vesicles secrete a significant proportion of the fluid that ultimately becomes semen. Lipofuscin granules from dead epithelial cells give the secretion its yellowish color. Seminal vesicle fluid is alkaline, resulting in human semen having a mildly alkaline pH.[3] The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. Acidic ejaculate (pH <7.2) may be associated with Ejaculatory duct obstruction. The vesicle produces a substance that causes the semen to become sticky/jelly-like after ejaculation, which is thought to be useful in keeping the semen near the womb. The thick secretions from the seminal vesicles contain proteins, enzymes, fructose, mucus, vitamin C, flavins, phosphorylcholine and prostaglandins.

8) Prostate Gland: The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance, that usually constitutes 20-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The alkalinization of semen is primarily accomplished through secretion from the seminal vesicles. The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those expelled in prostatic fluid have better motility, longer survival and better protection of the genetic material (DNA). The prostate also contains some smooth muscles that help expel semen during ejaculation. Prostatic secretions vary among species. They are generally composed of simple sugars and are often slightly alkaline.

9) Bulbourethral gland: During sexual arousal each gland produces a clear, salty, viscous secretion known as pre-ejaculate. This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizing traces of acidic urine in the urethra,[2] and helps flush out any residual urine or foreign matter. It is possible for this fluid to pick up sperm, remaining in the urethral bulb from previous ejaculations, and carry them out prior to the next ejaculation.
List the basic anatomy of a sperm cell and where they are produced and stored.
.
Sperm (single=spermatazoa) are produced by the testicles in the seminiferous tubules and stored and nutured in the epididymis. They are a single cell consisting of a head (cell body) and tail (flagella). They contain lots of mitochondria. The acrosome is an organelle that develops over the anterior half of the head in the spermatozoa (sperm cells) of many animals. It is a cap-like structure derived from the Golgi apparatus. The acrosome contains digestive enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum.
Name and describe the specific purpose of each substance secreted into the ejaculate by the seminal vesicles, prostate gland and bulbourethral gland (cowper's gland).
Seminal Vesicles: Secrete fructose rich fluid that serves as an energy source for the sperm. The two seminal vesicles contribute approximately 60 percent of the fluids passed from the human male during ejaculation. The secretion of the seminal vesicles constitutes the bulk of the seminal fluid (semen). It is a thick fluid that contains the sugar fructose, proteins, citric acid, inorganic phosphorus, potassium, and prostaglandins. Once this fluid joins the sperm in the ejaculatory duct, fructose acts as the main energy source for the sperm outside the body. Prostaglandins are believed to aid fertilization by causing the mucous lining of the cervix to be more receptive to sperm as well as by aiding the movement of the sperm toward the ovum with peristaltic contractions of the uterus and fallopian tubes.

Prostate Gland: Releases an alkaline milky fluid that protects the sperm from the acidic environment of the female. The function of the prostate is to secrete a slightly alkaline fluid, milky or white in appearance,[5] that usually constitutes 20-30% of the volume of the semen along with spermatozoa and seminal vesicle fluid. The alkalinity of semen helps neutralize the acidity of the vaginal tract, prolonging the lifespan of sperm. The alkalinization of semen is primarily accomplished through secretion from the seminal vesicles.[6] The prostatic fluid is expelled in the first ejaculate fractions, together with most of the spermatozoa. In comparison with the few spermatozoa expelled together with mainly seminal vesicular fluid, those expelled in prostatic fluid have better motility, longer survival and better protection of the genetic material (DNA). Generally composed of simple sugars and are often slightly alkaline.

Bulbourethral Gland: Release a small amount of viscous fluid prior to ejaculation. During sexual arousal each gland produces a clear, salty, viscous secretion known as pre-ejaculate. This fluid helps to lubricate the urethra for spermatozoa to pass through, neutralizing traces of acidic urine in the urethra,[2] and helps flush out any residual urine or foreign matter. It is possible for this fluid to pick up sperm, remaining in the urethral bulb from previous ejaculations, and carry them out prior to the next ejaculation.
Describe the ejaculatory pathway.
Seminiferous Tubules
Epididymis
Vas deferens
(seminal vesicles, prostate gland, bulbourethral gland all secrete various lubricants and nutrients)
Urethra
Penis
Describe the basic anatomy and function of the following:

1) Vagina
2) Cervix
3) Uterus
4) Fallopian Tubes
5) Ovaries
1) Vagina: A fibromuscular tubular tract which is a sex organ and has two main functions; sexual intercourse and childbirth.
2) Cervix: The lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. The cervix has an opening to allow sperm and menstrual fluid to move through.
3) Uterus: The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. It implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth.
4) Fallopian Tubes: Two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction.
5) Ovaries: The ovaries aren't attached to the fallopian tubes but to the outer layer of the uterus via the ovarian ligaments. Usually each ovary takes turns releasing eggs every month; however, if there was a case where one ovary was absent or dysfunctional then the other ovary would continue providing eggs to be released. Ovaries secrete both estrogen and progesterone. Estrogen is responsible for the appearance of secondary sex characteristics of anatomically female people at puberty and for the maturation and maintenance of the reproductive organs in their mature functional state. Progesterone functions with estrogen by promoting menstrual cycle changes in the endometrium.
Describe the development of an egg.
Oogenesis. At birth, all of the immature ova, know as primary oocytes, that a female will produce during her lifetime are already in her ovaries. Primary oocytes are diploid cells that form by mitosis in the ovary. After the first period one primary oocyted per month completes meiosis I, yielding two daughter cells of unequal size-a secondary oocyte and a small cell known as a polar body. The secondary oocyte is expelled from the follicle during ovulation. Meiosis II does not occur until fertilization. After fertilization it is called an ovum. (At birth the oocyte is arrested at Prophase I.)
Describe the menstrual cycle and the hormones involved.
1. Begins with FSH, which stimulates the maturation of the follicle in the ovary (FSH also stimulates maturation of sperm in males)

2. LH then stimulates cells in the ovaries to secrete estrogen (estradiol), which prepares the uterine wall for pregnancy.

3. Just before ovulation, a surge in estrogen causes a surge in LH (luteal surge), which causes ovulation.

4. If no fertilization occurs the corpeus luteum degrades and the menstrual lining sluffs off.

5. If implantation does occur, the corpus luteum secretes estrogen and progesterone, maintaining pregnancy.

(The corpus luteum develops from an ovarian follicle during the luteal phase of the menstrual cycle or estrous cycle, following the release of a secondary oocyte from the follicle during ovulation. While the oocyte (later the zygote if fertilization occurs) traverses the Fallopian tube into the uterus, the corpus luteum remains in the ovary.)
Where does fertilization and implantation normally occur?
Fertilization usually occurs in the fallopian tubes. Sperm and egg, traveling toward one another, generally meet here. Implantation normally occurs in the uterus, but can occur in the fallopian tubes, leading to a "tubal," or "ectopic" pregnancy.
Describe what happens with low and high levels of estrogen/progesterone?
If they go up unexpectedly, high levels could cause unexpected mensturation. This is sometimes see in elderly women given estrogen/progesterone therapy for treatment of osteoporosis. By contrast, below normal levels of estrogen/progesterone lead to the symptoms of menopause. Of course to have menstruation, or the sloughing off of the uterine lining, we must first have a build-up of that lining. Build-up and maintenance of the uterine lining is one of the normal functions associated with estrogen/progesterone.
What are the general symptoms of menopause?
Hot flashes, vaginal dryness, atrophy of breast tissue. All of these are the result of decreased estrogen and progesterone levels.
Describe what cleavage, morula, blastocyst, gastrulation, and neurulation are.
Cleavage: Mitosis without change in size. This begins while the zygote is still in the Fallopian tube.

Morula: 8-cell zygote. At this stage the embryo does not grow during cleavage. Any one of these eight cells at this stage could produce a complete individual.

Blastocyst: The morula continue to divide for four days forming a hollow ball filled with fluid called the blastocyst. It is the blastocyst that lodges int the uterus during implantation.

Gastrulation: at about week 2, cells migrate to form the three germ layers.

Neurulation: at about week 3, the notochord forms from the mesoderm and induces the overlying ectoderm to form the neural plate, which becomes the neural tube, then the spinal cord.
What structures consist of the ectoderm, mesoderm, and endoderm?
Ectoderm: epidermis, nails, tooth enamel, lens of the eye, pituitary gland, central, peripheral, and autonomic nervous system.

Mesoderm: Dermis, muscle, bone, connective tissue, kidneys, genitalia, and most internal organs EXCEPT the liver and pancreas.

Endoderm: the entire digestive tract, thyroid, parathyroid, urinary bladder, the LINING ONLY of the lungs, the liver and pancreas.
1.
1) C ; Answer choices A and D both support the concept that information inherent in each cell determines differentiation as evidenced by the fact that removing a cell and placing it in a new environment has no effect. Answer choice B indicates that each of the two split cells developed into a complete creature, which would support the idea that the entire set of determinants was found genetically in each cell. If Scientist A were correct, we might expect both cells to differentiate into matching tissues due to environmental factors, not into highly variable, complete organisms. Thus, C is the best answer. If a cell develops differently based on its surrounding cells, this would support Scientist A's hypothesis.
2.
2) B ; Statement I is true, all cells in the human body do have a complete copy of the genome. Statement II is also true; an excellent example of this is the cells of the endoderm releasing local hormones that "induce" the overlying ectoderm to develop into the dorsal hollow nerve chord. Statement III is true in general, for all cells beginning their development. At some point near the end of development, however, they will lose this totipotent ability, and thus the statement is NOT true as written.
3. Osteoporosis, a condition causing chronic loss of bone mass, is nearly twice as common in women as it is in men. This is most likely because:

A. women have a different bone structure than men
B. women have different calcium uptake mechanisms than men
C. women are born with fewer bones than men
D. women are born with lower bone density than men
3) D; Answer D is the correct answer. It's not one of those "jump out at you as right"-type answers, but the other three should be easy to confidently eliminate. Women are indeed born with lower bone density and tend to not increase bone density during life via heavy lifting as do men. Answer A is false because there are no systematic bone differences based on sex that would account for osteoporosis. Answer B is false because men and women both have the same physiology when it comes to calcium uptake. Had it said something about hormonal differences, this could have been a correct answer. Answer C is false because women do not have fewer bones. Answer D is thus the best answer.
5. Aging women are often prescribed estrogen supplements to help offset the effects of osteoporosis. Which of the following is a likely result of such treatment?

A. Decreased pituitary activity due to negative feedback
B. Inappropriate lactation not associated with pregnancy or childbirth
C. Loss of female secondary sex characteristics
D. Increased pituitary activity due to positive feedback
5) A; Answer B is false because oxytocin and prolactin are associated with lactation and let down, not estrogen. C is false because estrogen actually stimulates female secondary sex characteristics. Finally, Answer D is false because FSH secretion by the pituitary would be inhibited by the presence of estrogen, not stimulated by it. For the same reason, Answer A is true. Estrogens (or progesterone, or testosterone) inhibit the release of GnRH (Gonadotropin Releasing Hormone) from the hypothalamus. GnRH is the hormone that prompts release of FSH from the pituitary, which stimulates the follicle to release estrogens and progesterone (or the sertoli cells to release testosterone in males). Estrogen is the final step in the cycle and if it is present, it will inhibit GnRH, stopping the loop.
8.
8) D; Answer A is false because it leaves out the embryo and the corpeus luteum. Answer B is false because it leaves out the hypothalamus and because FSH and LH are anterior pituitary hormones NOT posterior pituitary. Answer C is incorrect because it also leaves out the hypothalamus. Answer D, however, correctly orders all of the major structures involved in ovulation thru pregnancy in females. If you aren't sure what each structure does and which hormone it secretes, review this topic with your tutor.
12. Which of the following statements is/are true regarding the organization of mammalian skeletal muscle?

I. Myofibrils are bundled into groups called fasciculi
II. T-tubules located in the sarcoplasmic reticulum allow for conduction of action potentials deep into the muscle fiber
III. Each muscle cell contains multiple nuclei

A. I only
B. III only
C. II and III
D. I, II, and III
12) B; Statement I is false because myofibrils are bundled into muscle fibers or cells, not fasciculi. Statement II is false because T-tubules are invaginations of the sarcolemma (cell membrane) not the sarcoplasmic reticulum (specialized ER). Finally, Statement III is true, making Answer B the best answer.
36. An osteoblast cell found in a newborn child's bone structure ultimately originated from:

A. a totipotent cell that could have developed into any other cell type given the correct environmental conditions
B. a pluripotent cell that could have developed into muscle, bone or skin, but not other cell types
C. a totipotent cell genetically programmed to develop into a bone cell
D. a pluripotent cell influenced by both genetic and environmental factors
36) A; Answer B is false because, although at some point along the way the cell would have been pluripotent (partially differentiated), it "ultimately" originated (as the question stem states) from a totipotent cell. Answer C is false because all cells contain the same exact DNA. Finally, Answer D is false because, as said before, it was originally totipotent. Answer A is thus correct. Originally, embryonic cells are totipotent and can develop into ANY of the cells of the body.
40. An assay of a bone sample from the hip of a fracture patient is expected to contain which of the following?

I. Phosphorous
II. Calcium
III. Oxygen
IV. Nitrogen

A. I only
B. I and II
C. I, II, and III
D. I, II, III, and IV
40) D; Bone is made of hydroxyapetite, which contains Ca, PO4 and -OH. This makes Statements I thru III true. Nitrogen is NOT part of bone matrix, but it would be found in a sample of hip bone because it would be found in the proteins within the bone cells. Thus, all of the listed elements would be expected and D is the best answer.
What are the functions of the Kidney
Maintain homeostasis of bodily fluids (especially blood plasma)
Control plasma pH
regulate blood volume and pressure
...
What is the Renal Pelvis and Ureter?
...
...
Draw a nephron, label the parts, and describe the function of each
...
Compare and contrast ureters and urethra
The ureters carry urine from the renal pelvis portion of the kidneys to the bladder. The urethra carries urine from the bladder to the external urinary orifice. You have two ureters, but only one urethra.
Describe the interplay between:

The juxtaglomerular apparatus, the renin-angiotensin pathway, aldosterone, and the distal convoluted tubules of the kidney
The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance.
When blood volume is low, juxtaglomerular cells in the kidneys secrete renin directly into circulation. Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin converting enzyme found in the lungs. Angiotensin II is a potent vaso-active peptide that causes blood vessels to constrict, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the distal convoluted tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure.

If the renin-angiotensin-aldosterone system is too active, blood pressure will be too high. There are many drugs that interrupt different steps in this system to lower blood pressure
juxtaglomerular apparatus
a specialized region of the nephron responsible for production and secretion of the enzyme renin
What does ADH do?
acts on the kidney's collecting duct making it permeable to water. In the absence of ADH the collecting duct is impermeable to water. Because the collecting duct passes through the highly-concentrated medulla, as soon as the membrane become permeable there is a large net flow of water out of the filtrate, concentrating the urine.

The net effect = water retention and increased blood pressure
What makes up the nervous system?
includes the brain, spinal cord, peripheral nerves, neural support cells AND sensory organs such as the eyes and ears
...
Neurons are:

(1)Frozen in G₀ phase (unable to divide)
(2) Depend entirely on glucose for energy
(3) Don't require insulin for glucose uptake
(4) Have very low glycogen and Oxygen storage capability and thus require high perfusion (blood flow)
The opening of the voltage-gated sodium channels causes a sudden spike in the membrane potential, from _____ mV to somewhere around ____mV

What is this process referred to as?
-70 mV to around +40mV

Depolarization
About what voltage is th3e threshold potential at?
-55mV
When do the K⁺ channels open in action potential propagation?
Just before maximum depolarization is reached, the Na⁺ channels begin to close and the K⁺ channels begin to open
How low does the membrane potential go during hyperolarization and why?
The potassium channels are somewhat slow to close as the membrane potential approaches -70 mV. Thus, the membrane potential actually dips to around -90mV before gradually returning to the resting potential.
"Absolute refractory period" vs "relative refractory period"
After initiation of an action potential, the refractory period is defined two ways:

(1) The absolute refractory period is the interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied.

(2)The relative refractory period is the interval immediately following during which initiation of a second action potential is inhibited but not impossible

The relative refractory period immediately follows the absolute
Why does it take a stronger stimulus than normal to cause an action potential during the relative refractory period?
hyperpolarization of the membrane, that is, the membrane potential becomes transiently more negative than the normal resting potential. Until the potassium conductance returns to the resting value, a greater stimulus will be required to reach the initiation threshold for a second depolarization. The return to the equilibrium resting potential marks the end of the relative refractory period
What is the slowest part of signal transmission down a nerve?
Transmission across the synapse is by far the slowest part of signal transmission
Where are Electrical Synapses found in humans?
The retina, smooth muscle, cardiac muscle, and the CNS
Brownian motion
the presumably random drifting of particles suspended in a fluid (a liquid or a gas) or the mathematical model used to describe such random movements, which is often called a particle theory.
What is another term for an activator?

Inhibitor?
Agonist = activator

Antagonist = inhibitor
What are ependymal cells
cells lining the cerebrospinal fluid cavities
What percentage of all neurons are interneurons?
90%
All of the following changes to the physiology of the cell membrane of a neuron would decrease the sensitivity of that neuron to the propagation of a new action potential, EXCEPT:

A. a complete inhibition of ATP production and availability in the cell
B. administration of a drug that up-regulates the function of the sodium-potassium pump
C. increased selective permeability of the neuronal membrane to sodium ions
D. increased rate of diffusion of potassium ions relative to sodium ions
C; See manual for explication
Why is visceral pain often referred (i.e., felt at a location other than the actual source)?
It is part of the sensory subdivision of the autonomic nervous system which is not well developed.
What two pain divisions make up the motor subdivision of the autonomic nervous system?
Sympathetic and Parasympathetic
What type of neurotransmitter is found at the ganglia and effectors of the sympathetic nervous system?
Acetocholine at the ganglia and norepinephrine at the effector
What is the neurotransmitter used in the parasympathetic nervous system?
Acetylcholiine
Where are the neuron cell bodies located in the sympathetic nervous system?
far from the effectors
Where are the neuron cell bodies located in the parasympathetic nervous system?
very close to, or inside, the effector
Rods vs Cones
Rods = highly sensitive, perceive black and white only

Cones = less sensitive, perceive color
...
Draw a diagram of the human eye and label the following: Cornea, sclera, pupil, iris, aqueous humor, vitreous humor, lens, suspensory ligaments, ciliary muscles, retina, and optic nerve.
...
...
How do you correct far- and near-sightedness?
...
What does most of the bending of light rays?
Light rays are bent most by the cornea, and subsequently adjusted by the lens
What do the ciliary muscles do when you focus on a book very near your face?

What happens to the curvature of the lens? Focal point? power of the lens?
Ciliary muscles contract, lens becomes more curved (convex), focal point decreases and power increases.
What does the outer ear include?
The Pinna (earlobe) and auditory canal
What does the Middle Ear include?
Includes the tympanic membrane and three middle ear bones: Malleus, incus & stapes
What does the Inner ear include
the Cochlea, semicircular canals and the vestibulocochlear nerve
...
Draw and label all of the parts of the inner ear.
...
...
Draw a cross-section of the cochlea showing the three compartments and the organ of Corti.
...
Compare and Contrast:

Exocrine and Endocrine Glands
Exocrine glands release enzymes or other liquids into the external environment (which includes the digestive tract and epithelial lined orifices; substances released include sweat, oil, mucus, digestive enzymes, etc.)

Endocrine glands release hormones into the internal fluids of the body (e.g. blood, lymph, etc)
What hormones come from the Pancreas?
Gucagon and Insulin

(also releases several digestive enzymes, but this is an exocrine function: not an endocrine function)
What is the full name of the hormone hCG

What does it do?
human Chorionic Gonadotropin
What hormones are Steroids?
Cortisol and Aldosterone from the Adrenal Cortex
and
Estrogen, progesterone and Testosterone from the gonads
What hormones are tyrosines?
T₃/T₄ which are lipid-soluble

Epi/Norepi which are water-soluble
Patient A has high blood glucose levels. Which hormone is likely to be found in highest concentration in her blood?
Insulin
Patient B has low blood glucose levels. Which hormone is likely to be in highest concentration in his blood?
Glucagon
Patient A has osteoporosis. Which hormone will be found in highest concentration in her blood?
Parathyroid
Patient B suffers from calcinuria, a disease resulting in chronically low blood calcium. Which hormone will be found in highest concentration in his blood.
Calcitonin
Polycystic Ovary Syndrome results in numerous follicles, or fluid-filled egg sacs, forming on the surface of a woman's ovaries. Ovulation is greatly inhibited or irregular and multiple cysts build up over time. A researcher has discovered that female lab animals who are given high levels of "male hormones," called androgens, exhibit almost identical symptoms. The researcher hopes to develop a drug that associates with the androgens in a woman's body and prevents them from binding to their receptors. To be effective, it is important that the drug:

A. be lipid-soluble
B. be water-soluble
C. have a short half-life under physiological conditions
D. bind reversibly to its target
A
What organ secretes two types of hormones?
The Thyroid. It secretes both a tyrosine derivative and a peptide hormone
Which of the following best accounts for the fact that a stronger stimulus is required to initiate an action potential during the relative refractory period?

A. Compared with resting potential, sodium ion concentration inside the cell is much higher, requiring a larger threshold stimulus
B. Compared with resting potential, sodium ion concentration inside the cell is much lower, requiring a larger threshold stimulus.
C. Excess potassium ions inside the cell create a larger negative potential, which must be overome be a larger threshold stimulus.
D. Excess potassium ions outside the cell create a larger negative potential, which must be overcome by a larger threshold stimulus
D
Which or the following statements is/are true concerning the use of neurotransmitters in the autonomic nervous system?

I. All parasympathetic synapses utilize acetylchholine
II. All sympathetic synapses utilize acetylcholine
III. Both acetylcholine and norepinephrine are used by the parasympathetic nervous system
IV. Acetylcholine is used at pre-ganglionic synapses in the sympathetic nervous system

A. I and III
B. I and IV
C. II and III
C. II and IV
B
Which of the following most completely describes the nerve endings in the eye that cause pupil dilation?

A. Sympathetic, norepinephrine
B. Parasympathetic, acetylcholine
C. Sympathetic, acetylcholine
D. Parasympathetic, norepinephrine
A
As winter approaches, the Siberian muskrat gorges itself on high-carbohydrate food in order to store up fat for its long hibernation. Which of the following hormones is likely to be found in highest concentration in the muskrat's liver during the fall and winter, receptively?

A. glucagon, then insulin
B. insulin, then glucagon and cortisol
C. insulin, then glucagon
D. glucagon, then insulin and cortisol
B ; Recall that insulin and glucagon, like all hormones, tend to return things to normal physiological levels. Thus, while the muskrat is gorging on carbs, the blood concentration of glucose due to the absorption of these carbs will be higher than normal and insulin would be secreted to return things to normal. During the winter, there will be NO absorption because the muskrat won't be eating, so blood glucose will be lower than normal and glucagon will be present to raise the blood glucose levels to normal. Next, you must ask yourself what cortisol does? It is a stress hormone whose main effect is to promote gluconeogenesis (the reverse of glycolysis) and promote fat metabolism. This is very likely to be present during a stressful hibernation when the muskrat will need to accomplish both of these tasks in order to maintain its normal blood glucose levels. B is thus the best answer.
Patients with a new disease suffer from two main problems: 1) dangerously high blood pressure and 2) erratic, abnormally high calcium blood concentration.

Blood samples from affected patients show a very high concentration from an unknown protein. This protein is assayed and found to be a recognized human hormone. Based on the information in the passage, which of the following is most likely the identity of this hormone?

A. Calcitonin
B. PTH
C. Aldosterone
D. ADH
B ; Aldosterone and ADH would both account for only one symptom, Calcitonin (as mentioned above) would not account for any of them, and PTH could account for both (by its normal effect of increasing blood calcium and via an increase in blood pressure via increased osmolarity). Although it may be tempting to pick C or D, it is impossible to say that one is more likely than the other and B is the better answer because it accounts for both symptoms.
All of the following provide an accurate description of a human hormone and one of its major effects, EXCEPT:

A. FSH stimulates the development of sperm in males
B. Estrogen stimulates a dramatic increase in leutinizing hormone
C. Prolactin stimulates the secretion of milk from the mammory glands
D. Calcitonin inhibits the proliferation of osteoclasts
C ; Hopefully you're getting the point by now . . . that you really DO need to know that hormone chart inside and out. A will be marked wrong by many students because they think of the female reproductive system when they see FSH. In fact, it regulates both sexes similarly, stimulating the testes to develop and nurture gametes. Estrogen does cause an increase in LH during menstruation, known as the "luteal surge." Answer D is also true, calcitonin does inhibit osteoclasts. C, however, is false because prolactin stimulates milk production (lactation) not milk excretion (or "let down").
The hormone TSH most likely has its affect via which of the following mechanisms?

A. TSH dissolves through the nuclear membrane of thyroid cells into the cytoplasm, where it increases translation
B. TSH binds to a receptor on the cell membrane, where it initiates a cascade that increases the metabolic activity of thyroid cells.
C. TSH bind to a receptor on the cell membrane, where it initiates a cascade that increases transciption.
D. TSH dissolves through the nuclear membrane where it increases DNA replication
C ; TSH is a peptide hormone, so it CANNOT dissolve thru the membrane, eliminating answer choices A and D. B is false because an increase in metabolic activity would not have the effect which TSH has. TSH stimulates the thyroid to secrete T3 and T4, which in turn increases basal metabolic rate. To make this happen, TSH must in some way increase the transcription of DNA into the mRNA molecules that are then translated into T3 and T4 at the rough ER and exported from the cell; answer choice C describes this very action and is thus the best answer.
Which of the following statements best describes the mechanism of function of the inner ear?

A. The tympanic membrane, displaced by collisions with air molecules, displaces the malleus, then the incus, then the stapes, resulting in an increase in displacement at the oval window.
B. The ympanic membrane, displaced by collisions with air molecules, displaces the incus, then the malleus, then the stapes, resulting in an increase in pressure at the oval window
C. The tympanic membrane, displaced by sound waves, displaces the incus, the malleus, then the stapes, resulting in a decrease in pressure at the oval window.
D. The tympanic membrane, displaced by sound waves, displaces the malleus, then the incus, then the stapes, resulting in a decrease in displacement at the oval window
D ; First, note that both the term "displaced by collisions with air molecules" and the term "displaced by sound waves" are correct. The key here is to first find the choice with the correct order of bones: maleus, incus, then stapes. This narrows it to A or D. A is wrong and D is correct because the displacement at the oval window compared to the eardrum is DECREASED. This difference in input/output displacement creates the lever action of the ear and magnifies the pressure at the oval window.
Which of the following statment is/are true concerning the organ of corti?

I. Small microtuble-filled membrane extensions, called "hair cells" sense disturbances in the fluid and transmit these movements into neural signals
II. It is located inside the cochlea
III. it contains the Semi-Circular Canals, which help maintain balance and orientation

A. I only
B. II only
C. II and III
D. I and II
B; The Organ of Corti is the structure inside the cochlea that transfers fluid motions into a nerve signal. It does not contain microtubules (and doesn't contain cilia!), so Statement I is false. Statement II is true. Statement III is false because the semi-circular canals are not located within the Organ of Corti.
Name and describe the two types of digestion.
Physical Digestion: Chewing (mastication), churning in stomach, breaking into smaller pieces, including emulsification of fats by bile.

Chemical Digestion: All breakdown of food via breaking of bonds.
Provide a definition and basic function for each of the following:

1) Mouth
2) Pharynx
3) Larynx
4) Esophagus
5) Peristalsis
6) Stomach
7) Small Intestine (duodenum; jejunum; ileum)
8) Large Intestine
9) Colon (ascending; transverse; descending; sigmoid)
10) Rectum
11) Pancreas
12) Liver
13) Gall Bladder
1) Mouth:
2) Pharynx: The part of the throat situated immediately posterior to (behind) the mouth and nasal cavity. Propel the bolus (ball) of food down into the esophagus
3) Larynx: Voice box. Involved in breathing, sound production, and protecting the trachea against food aspiration.
4) Esophagus: Food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach. The entry to the esophagus opens only when swallowing or vomiting.
5) Peristalsis: Radially symmetrical contraction and relaxation of muscles which propagates in a wave down the muscular tube.
6) Stomach: Involved in the second phase of digestion, following mastication (chewing). The stomach releases proteases (protein-digesting enzymes such as pepsin) and hydrochloric acid, which kills or inhibits bacteria and provides the acidic pH of two for the proteases to work.
7) Small Intestine (duodenum; jejunum; ileum): Where much of the digestion and absorption of food takes place. Proteins and peptides are degraded into amino acids. Chemical breakdown begins in the stomach and continues in the large intestine. Lipids (fats) are degraded into fatty acids and glycerol. Pancreatic lipase breaks down triglycerides into free fatty acids and monoglycerides. Some carbohydrates are degraded into simple sugars, or monosaccharides (e.g., glucose). Other carbohydrates pass undigested into the large intestine and further handling by intestinal bacteria.
8) Large Intestine: Absorb water, Bacterial flora, the colon or large intestine produces no digestive enzymes.
9) Colon (ascending; transverse; descending; sigmoid): it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided (largely bacterial) fermentation of unabsorbed material occurs.
10) Rectum: The rectum intestinum acts as a temporary storage site for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the nervous system located in the rectal walls stimulate the desire to defecate.
11) Pancreas: The pancreas as an exocrine gland helps out the digestive system. It secretes pancreatic fluid that contains digestive enzymes that pass to the small intestine. These enzymes help to further break down the carbohydrates, proteins, and lipids (fats) in the chyme.
12) Liver: The liver produces and excretes bile (a yellowish liquid) required for emulsifying fats. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder.
13) Gall Bladder: A small organ that aids mainly in fat digestion and concentrates bile produced by the liver. It releases bile into the duodenum. The bile, originally produced in the liver, emulsifies fats in partly digested food.
Digestion begins at the mouth with the physical digestion of all food types and chemical digestion of _________ ONLY (via the enzyme _____).
Digestion begins at the mouth with the physical digestion of all food types and chemical digestion of Carbohydrates ONLY (via the enzyme α-amylase).
What is the name of the reaction by which amylase catalyses carbohydrate breakdown.
.
Hydrolysis
What is the name of the clump of food formed at the mouth?
Bolus
What are the functions of the stomach?
Functions include: Food storage, mixing, continuation of carbohydrate digestion (which started in the mouth), and the FIRST site of protein digestion. Without an adequate stomach, food moves too fast thru the digestive system, resulting in incomplete digestion and absorption.
Proteins in the stomach undergo _______, a reaction catalyzed by the enzyme ________. This enzyme begins as _________, an example of a _________.
Proteins in the stomach undergo proteolysis, a reaction catalyzed by the enzyme pepsin. This enzyme begins as pepsinogen, an example of a zymogen.
What are the four stomach lining cell types and what do they do?
1) Mucous Cells: Make and secrete mucous (into stomach/gastric pit)
NOTE: "Goblet Cells" are mucous secreting cells found in the linings of the intestines and respiratory tract. Don't confuse them with mucous cells.

2) Chief Cells: Make and secrete pepsinogen (into stomach/gastric pit)

3) Parietal Cells: Secrete HCl (into stomach/gastric pit). HCl is responsible for the acidity (pH=2) of the stomach. Parietal cells contain a lot of mitochondria (the amount of energy necessary to produce the concentrated acid is great).

4) G-Cells: Make and secrete gastrin. Gastrin is released into the blood (NOT into the stomach/gastric pit) where it circulates back to the parietal cells stimulating them to release HCl. Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells.
In addition to pepsin, what else assists in protein metabolism in the stomach?
The low pH of the stomach assists this process by denaturing the proteins.
Name the three sections of the small intestine and describe what happen in the small intestine and in what location.
Duodenum, Jejunum, Ileum

The majority of all digestion and absorption occurs in the small intestine (about 90%); digestion primarily in the duodenum and absorption primarily in the jejunum and ileum.
Provide a conceptual definition for each of the following:

1) Villi
2) Microvilli
3) Lacteal
4) Brush Border
1) Villi: The outermost layer of the small intestine contain finger-like projections called villi. The villi increase the surface area of the intestinal wall allowing for greater digestion and absorption.

2) Microvilli: On the apical (lumen side) surface of the cells of each villus are much smaller finger-like projections called microvilli. The microvilli increase the surface are of the intestinal wall still further.

3) Lacteal: Within each villus are a capillary network and a lymph vessel called a lacteal. Nutrients absorbed through the wall of the small intestine pass into the capillary network and the lacteal.

4) Brush Border: Under a light microscope the microvilli appear as a fuzzy covering. The fuzzy covering is called the brush border. The brush border contains membrane bound digestive enzymes, such as carbohydrate digesting enzymes, protein digesting enzymes, and nucleotide digesting enzymes.
Describe the function of the large intestine.
The major functions of the large intestine are water absorption and electrolyte absorption. The large intestine also contains the bacteria E. Coli. The bacteria produce vitamin K, B₁₂, thiamin, and riboflavin.

Whenever you get a large intestine question on the MCAT, think water reabsorption. Profuse water loss in the form of diarrhea often results when there is a problem with the large intestine. There is a mutualistic symbiosis between humans and bacteria in the large intestine. Bacteria get our leftovers; we get certain vitamins from them.
What type of gland is the pancreas?
It is both an endocrine and an exocrine gland. Exocrine for the digestive enzymes and endocrine for insulin and glucagon.
Where are pancreatic secretions emptied into the digestive system?
All pancreatic secretions empty into the upper end of the duodenum. Just before emptying into the duodenum the pancreatic duct is joined by the bile duct.
What is the glob of food called that leaves the stomach?
Chyme
What is the pH of the duodenum and how does it have that pH?
The duodenum has a pH of 6 due to the bicarbonate ion secreted by the pancreas.
What are the digestive enzymes secreted by the pancreas? Describe the function of each enzyme.
1) Trypsin: Degrade proteins into small polypeptides

2) Chymotrypsin: Degrade proteins into small polypeptides

3) Pancreatic amylase: Hydrolyzes polysaccharides to disaccharides and trisaccharides. Degrades nearly all the carbohydrates from the chyme into small glucose polymers. (Much more powerful than salivary amylase)

4) Lipase: Degrades fat, specifically triglycerides. Since the intestinal fluid is an aqueous solution, the fat clumps together, reducing its surface area. Bile emulsifies the fat, breaking it up into small particles without changing it chemically, thus increasing the surface area of the fat. The bile allows lipase to degrade it into mainly fatty acids and monoglycerides.

5) Ribonuclease: Nuclease that catalyzes the degradation of RNA into smaller components

6) Deoxyribonuclease: Nuclease that catalyzes the hydrolytic cleavage of phosphodiester linkages in the DNA backbone.
Describe the function of the Gall Bladder.
The gall bladder stores, but does NOT produce bile. Bile is produced in the liver. Bile emulsifies fats (breaks them apart into smaller pieces, increasing surface area). Bile does not digest the fat. Bile physically separates fat molecules, but does not break them down chemically.
List the functions of the liver.
Functions include:

1) Blood storage
2) Blood filtration
3) Carbohydrate metabolism/regulation
4) Fat metabolism/regulation
5) Protein metabolism/regulation
6) Detoxification
7) Erythrocyte destruction
8) Vitamin storage
9) Bile production
Describe where and how carbohydrates, proteins, and lipids are digested and absorbed.
Carbohydrates: Digestion begins in the mouth (amylase), continues in the stomach and is complete by the end of the small intestine. Broken down entirely to glucose BEFORE absorption; enter the blood stream (NOT the lacteal) and travel to the liver via the portal vein.

Proteins: Digestion begins in the stomach and is complete by the end of the small intestine. Broken down to amino acids before absorption; enter the blood stream (Not the lacteal) and travel to the liver. Failure to completely digest proteins into their amino acids may result in an allergic reaction.

Lipids: Digestion begins in the intestine (duodenum) and is complete by the end of the small intestine. It CANNOT begin prior to reaching the bile and lipase released into the upper duodenum. Triglycerides are broken down to fatty acids, transported across the membrane (villi), then reformed into triglycerides. Lipids enter the lacteals (NOT the blood stream). To travel in blood or lymph all lipids require either a protein carrier such as albumin, or must be formed into a chylomicron or micelle.
List the structures that air passes through during inhalation.
Mouth/Nose → pharynx → larynx → trachea → bronchi → bronchioles → alveoli
Provide a definition for the following terms:

1) tidal volume
2) reserve volume
3) residual volume
4) vital capacity
.
1) tidal volume: is the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied.
2) reserve volume: (Expiratory reserve volume): the maximal volume of air that can be exhaled from the end-expiratory position. (Inspiratory reserve volume): the maximal volume that can be inhaled from the end-inspiratory level
3) residual volume: the volume of air remaining in the lungs after a maximal exhalation.
4) vital capacity: the maximum amount of air a person can expel from the lungs after a maximum inspiration.
Where does the diaphragm move when contracted/relaxed? Where does the diaphragm move during inhalation exhalation?
The diaphragm moves DOWN when it is CONTRACTED and is curved UPWARD when it is RELAXED.

THe diaphragm moves DOWN during INHALATION and UP during EXHALATION.
Describe the structure of hemoglobin and explain how many oxygen molecules can bind to a single hemoglobin.
Hemoglobin is a quaternary protein made of four polypeptide subunits, 2 alpha and 2 beta. Each polypeptide subunit has an Fe-containing "heme" group at its center. Each heme can hold one O₂ molecule. Therefore, a single hemoglobin can hold a total of 4 O₂ molecules. When on O₂ molecule binds with an iron atom in hemoglobin, oxygenation of the other heme groups is accelerated. Similarly, release of an O₂ molecule by any of the heme groups, accelerates release by the others.
Draw an Oxygen Dissociation Curve. Show the shape of the curve for both O₂ binding and CO binding. Demonstrate and describe the effects of CO₂, H⁺, BPG, and temperature on the O₂ curve.
.
As O₂ pressure increases, the O₂ saturation of hemoglobin increases sigmoidally. The dissociation curve shows the percent of hemoglobin that is bound with oxygen at various partial pressures of oxygen.

The oxygen dissociation curve is shifted to the right by an increase in carbon dioxide pressure, hydrogen ion concentration, temperature and presence of BPG. A shift to the right indicates a lowering of hemoglobin's affinity for oxygen.

Carbon monoxide has more than 200 times greater affinity for hemoglobin than does oxygen but shifts the curve to the left.
How is CO₂ carried in the blood?
CO₂ is mostly carried in the blood in the form of bicarbonate. Through the reaction:

CO₂ + H₂O → HCO₃⁻ + H⁺

CO₂ is converted to bicarbonate in the red blood cells through the enzyme carbonic anhydrase.

The greater the pressure of carbon dioxide, the greater the blood content of carbon dioxide. Deoxygenation of the blood increases its ability to carry carbon dioxide; this property is the Haldane effect. Conversely, oxygenated blood has a reduced capacity for carbon dioxide.
How does breathing affect the level of CO₂ in the blood and the pH of the blood?
A person's breathing rate influences the level of CO2 in their blood. Breathing that is too slow or shallow causes respiratory acidosis, while breathing that is too rapid leads to hyperventilation, which can cause respiratory alkalosis.

Respiratory acidosis is a medical condition in which decreased ventilation (hypoventilation) causes increased blood carbon dioxide concentration and decreased pH (a condition generally called acidosis). Carbon dioxide is produced constantly as the body's cells respire, and this CO₂ will accumulate rapidly if the lungs do not adequately expel it through alveolar ventilation. Alveolar hypoventilation thus leads to an increased PaCO₂ (called hypercapnia). The increase in PaCO₂ in turn decreases the PaCO₂/HCO₃− ratio and decreases pH.

Alkalosis refers to a condition reducing hydrogen ion concentration of arterial blood plasma (alkalemia). The main cause of respiratory alkalosis is hyperventilation, resulting in a loss of carbon dioxide and subsequent raising of blood pH.
Label the following on a heart:

1) SVC
2) IVC
3) Right Atrium
4) Left Atrium
5) Pulmonary Artery
6) Pulmonary Vein
7) Right Ventricle
8) Left Ventricle
9) Aorta
.
List the flow of blood in the systemic circulation beginning with the ventricle and ending with the atrium.
Blood flows from the left ventricle, thru the arteries, arterioles, capillaries, venules, veins, vena cava and back to the right atrium.
List the flow of blood in the pulmonary circulation beginning with the ventricle and ending with the atrium.
Blood flows from the right ventricle thru the pulmonary arteries to the lungs and back thru the pulmonary veins to the left atrium.
Draw and describe the following on a diagram of the heart:

1) SA Node
2) AV Node
3) Bundle of His
4) Purkinje Fibers

Also discuss the following as they apply to the heart:

autorhythmic, electrical synapses, and gap junctions
.
The heart contracts automatically, paced by a group of specialized cardiac muscle cells called the SA node. The SA node is autorhythmic (contracts by itself at regular intervals), spreading its contractions to the surrounding cardiac muscles via electrical synapses made from gap junctions. The pace of the SA node is faster than normal heartbeats but the parasympathetic vagus nerve innervates the SA node, slowing the contractions. The AP generated by the SA node spreads around both atria causing them to contract, and , at the same time, spreads to the AV node. The AV node is slower to contract, creating a delay which allows the atria to finish their contraction, and to squeeze their contents into the ventricles before the ventricles begin to contract. From the AV node, the AP moves down conductive fibers called the bundle of His. The AP branches out through the ventricular walls via conductive fibers called Purkinje fibers. The Purkinje fibers in the ventricles allow for a more unified and stronger contraction.
What affect does the sympathetic and parasympathetic NS have on heart rate and BP?
Sympathetic NS: Increases heart rate and blood pressure

Parasympathetic NS: Decreases heart rate and blood pressure
List the different types of blood vessels and differentiate between arteries and veins.
Arteries → Arterioles → Capillaries → Venules → Veins

Arteries: muscular, thick-walled, PUSH blood thru via rhythmic contraction

Veins: little to no musculature, thin-walled, rely on valve system
Describe how the interplay of hydrostatic and osmotic pressure accounts for the flow of fluid into and out of the capillaries.
.
As blood flows into a capillary, hydrostatic pressure is greater than osmotic pressure, and net fluid flow is out of the capillary, and into the interstitium. Although osmotic pressure remains relatively constant throughout the capillary, hydrostatic pressure drops from the arteriole end to the venule end. Thus, osmotic pressure overcomes hydrostatic pressure near the venule end of a capillary, and net fluid flow is into the capillary and out of the interstitium. The net result of fluid exchange by the capillaries is a 10% loss of fluid to the interstitium.
Draw a graph for each of the following:

a) cross-sectional area vs. blood vessel type
b) velocity vs. blood vessel type
c) blood pressure vs. blood vessel type

What equation helps determine the velocity?
.
A single artery is much bigger than a capillary, but there are far more capillaries than arteries. The total cross-sectional area of all those capillaries put together is much greater than the cross sectional area of a single aorta or a few arteries. Blood flow follows the equation, Q=AV, so velocity is greatest in the arteries where cross sectional area is smallest, and velocity is lowest where cross sectional area is the greatest.
List the contents of blood.
1) White blood cells (leukocytes)
2) Red blood cells (erythrocytes)
3) Antibodies (immunoglobulins)
4) Clotting Factors (i.e., fibrinogen)
5) Transport Proteins (i.e., albumin)
6) Platelets
What type of tissue is blood?
Connective
Do immature and/or mature RBCs have a nucleus or other organelles?
Immature RBCs start out with a nucleus and organelles but these disappear as it matures. Mature RBCs have NO NUCLEUS or other organelles.
Do RBCs reproduces or undergo mitosis?
RBCs have no organelles, not even a nucleus, which means they do not reproduce nor undergo mitosis.
Do WBCs have organelles? What is their function?
Yes. Protect the body from foreign invaders.
What are the two types of leukocytes, give examples of each, how long do they live?
Granulocytes: neutrophils, eosinophils, basophils (Live for hours to days)

Agranulocytes: monocytes (become macrophages), lymphocytes, and megaharyocytes (Live for months to years)

Granulocytes function non-specifically against all infective agents, whereas most agranulocytes work against specific agents of infection. Thus, agranulocytes need to hang around in case the same infective agent returns; granulocytes multiply quickly against any infection, and then die once the infection is gone.
What are platelets? What do they do?
Tiny membrane bound drops of cytoplasm. They are sticky when exposed to injured epithelium and non-sticky to healthy epithelium. If they encounter injured epithelium, they release chemicals that activate other platelets and clotting factors.
What do all blood cells develop from and where? What is this process called?
Stem cells in the bone marrow. Hematopoeisis
List the four types of blood and describe which ones can receive blood from which ones.
A = A antigens only
B = B antigens only
AB = A and B antigens
O = No antigens

Always focus on the recipient. If a person's immune system sees anything it doesn't have on its own blood cell membranes, it will attack it and coagulation/rejections will result.

A can receive A and O
B can receive B and O
AB can receive A, B, AB, and O
O can receive O
What is the function of the lymphatic system?
Gather excess interstitial fluid and return it to the blood; remove from the interstitial spaces proteins and other molecules too big to be taken up by the capillaries; monitor the blood and lymph for infection.
What are lymph nodes filled with? Why do lymph nodes swell during infection/disease?
Lymph nodes are filled with lymphocytes. In response to antigens, the lymphocytes in the lymph node make an antibody which will go out of the lymph node into circulation, seek, and target the pathogen producing the antigen by targeting it for destruction by other cells and complement. Other immune system cells will be made to fight the infection and "sent" to the lymph nodes. The increased numbers of immune system cells fighting the infection will make the node expand and become "swollen."
Describe the lymph vessels; what are they similar to?
They are a lot like veins; one-way valves used to move the lymph; single cells overlap slightly creating a trap door that allows things in, but not back out. The lymph system eventually dumps back into the blood at the vena cava.
Describe what Innate Immunity is.
NON-SPECIFIC attack of antigens. Includes all immune reponses that are NOT specific to one particular virus, bacteria, pathogen, etc. Examples include: skin, stomach acid, enzymes in the mucous and saliva, digestive enzymes, blood chemicals, fevers, inflammation and non-specific phagocytosis.
What type of cells participate in innate immunity and what type of cells participate in acquired immunity?
Innate Immunity: Granulocytes
Acquired Immunity: Agranulocytes
Describe what acquired immunity is.
SPECIFIC response to one particular virus, bacteria or other pathogen based upon prior exposure. There are two types of acquired immunity: Humoral and Cell-Mediated.
Describe Humoral immunity. What type of immunity is it (innate/acquired) and what cells are involved. What is Primary Response and Secondary Response?
Humoral immunity is one type of acquired immunity. It is also called B-Cell Immunity. It involves B-Cells (B-Lymphocytes). IF YOU SEE B-CELLS, THINK HUMORAL IMMUNITY. B Cells develop and mature in the bone marrow and liver. Each B Cell produces ONLY ONE of a certain kind of protein receptor on its membrane called an antibody. Each antibody will recognize and bind with one other foreign particle called an antigen. If an antigen binds to a B-Cell's antibody, the B-Cell will differentiate into a plasma cell and and memory B-Cell. The plasma cells rapidly manufacture free antibodies and release them into the blood. The memory B-Cells multiply and remain in the blood, preparing the body for a second infection.

Primary Response = the immune system's first exposure and reaction to a pathogen.

Secondary Response = the immune system's response to that SAME pathogen during subsequent exposures.
Describe Cell-Mediated immunity. What type of immunity is it (innate/acquired) and what cells are involved.
Cell-Mediated immunity is one type of Acquired immunity. It is also called T-Cell Immunity. It involves T-Cells (T-Lymphocytes). IF YOU SEE T-CELL, THINK CELL-MEDIATED IMMUNITY. T-cells start in the bone marrow like B-Cells, but mature in the thymus. Also like B-Cells, they have an antibody protein on their membrane. UNLIKE B-Cells, they NEVER produce free antibodies. Instead, they are "tested" in the thymus against the host's own membrane proteins (called "self-antigens"). All T-Cells matching a self-protein are destroyed, leaving only cells that will recognize invaders. T-Cells that pass this test will differentiate into one of the following T-Cell types:

Helper T-Cells: Activate other cells, Killer T-Cells, Suppressor T-Cells and B-Cells (HIV attacks helper T-Cells)

Memory T-Cells: These exist, but forget about them for the MCAT. IF you see "memory," think Humoral Immunity.

Suppressor T-Cells: Suppress other lymphocytes and the immune system in general, thereby preventing self-attack. Problems here lead to autoimmune disease.

Killer T-Cells: Bind to the body's own diseased or virus-invaded cells and inject perforin, destroying the cell.
2.
2) B; Answer A is false because an increased pH actually means a LESS acidic solution. Answer C is obviously wrong because the question stem directly tells us that pepsin is secreted by the chief cells. If you didn't pick this up, you likely aren't reading as carefully as you need to. In any event, Answers C and D both are wrong because pepsin secretion is regulated by gastrin, and prior to that by stomach contents, not by pH levels. Answer B is thus the best answer. It is quite common for enzymes, being proteins, to lose some of their 3-D structure as pH changes.
4. Which of the following is NOT a function of the respiratory system?

I. Exchange carbon dioxide at the lungs
II. Pick up oxygen at the tissues
III. Assist the immune system in preventing and fighting infection

A. I only
B. II only
C. I and III
D. II and III
4) B; Statement I is true, carbon dioxide is definitely exchanged at the alveoli in the lungs. Statement II is false because oxygen is released at the tissues, not picked up. Statement III is true because the nasal passages both filter air to prevent infection and increase mucus secretion during an infection to sweep out pathogens.
7.
7) C; The capillary is an amazing structure in that it pumps things in and out of the blood without a pump system. This exchange is all accomplished by an interplay between osmotic and hydrostatic pressure. Hydrostatic pressure is high entering the capillary from the arteriolar side and decreases across the capillary; at the same time, osmotic pressure increases so that at the far venous end of the capillary there is a net flow into the capillary. Answer C is the only answer that reflects these facts.
9.
9) D; The clue here, is that Leptin allows for communication between the brain and the digestive system, which is a clear endocrine function that would be carried out by a hormone. Neurotransmitters are involved in communication between neurons and between neurons and muscles/glands. Digestive enzymes "eat" various biomolecules and would be dangerous were they circulating in the blood to carry messages between the brain and digestive system.
10.
10) C; Answer A is false because microvilli do not contain cilia and are not made of microtubules. Answer B is false because ependymal cells are not part of the digestive system. Answer D is false because this would involve normal transcription and translation and no mictrotubules. Answer C, however would be affected because microtubules make up the spindle apparatus.
11.
11) B; Be careful here. You need to know what effect the bicarbonate coming "out of solution" has on the carbon dioxide blood dissolution equation. Decreasing the solubility of bicarbonate basically means that more will precipitate out and it is thus equivalent to removing it. This will shift the equilibrium to the right to compensate, raising hydrogen ion concentration and lowering pH.
15. Vasoconstriction is employed by the body in accomplishing all of the following, EXCEPT:

A. maintenance of homeostasis on a hot day
B. prevention of blood loss after injury
C. response to a parasympathetic stimulus
D. response to a sympathetic stimulus
15) A; Answer B is false because vasoconstriction IS utilized to prevent blood loss at an injury site. Answers C and D are both false because vasoconstriction can be part of both a fight and a flight response. Answer A is the correct answer because vasodilation would be used on a hot day rather than vasoconstriction.
23.
23) A; Statement I is true, these are all found in the stomach lining. Statement II is false because G-cells are actually an example of a single-cell endocrine gland. They release Gastrin into the blood and lymph, rather than into the gut. This also makes statement III fasle; and A is thus the best answer.
24.
24) B; Answer A is illogical because absorption doesn't occur in the stomach. Answer C is false because water absorption happens at the large intestine, not the stomach. Answer D is nonsense—tying together an answer with a totally unrelated explanation (watch out for this—the MCAT does it often). Answer B is the correct answer. If the stomach is markedly smaller, there will be less protein digestion occurring here and the intestine may not be able to keep up. Incomplete digestion is a logical result.
32. Which of the following does NOT contribute to the body's innate immunity?

A. fever during a secondary response
B. acid in the stomach
C. inflammation following an injury
D. macrophages
32) A; All of the items listed, including fever, contribute to innate immunity and you should know them. The trick here is to recognize that the question states "fever during a SECONDARY response." Secondary responses are part of acquired, not innate immunity. Macrophages can be thought of as playing a part in both innate and acquired immunity because they randomly engulf foreign bodies, but they are also the ones who dispose of foreign cells after they have been marked by antibodies.
33. The blood from a patient with an autoimmune disease is teste and is found to contain high concentrations of free antibodies, cytosol, organelles and other cellular parts. Which of the following is the most likely cause?

A. hyperactivity of cell-mediated immunity
B. hyperactivity of humoral immunity
C. hypoactivity of humoral immunity
D. hyperactivity of both cell-mediated and humoral immunity
33) D; The observed response would be attributable to cell-mediated immunity because of the lysed cell parts. It is cell-mediated immunity that includes killer t-cells that attack our own diseased cells. The anitboies, however are associated strictly with humoral innumity and thus D is the most complete answer.
37. Which of the following nutrients is/are NOT absorbed into capillaries located within the wall of the small intestine?

I. fats
II. carbohydrates
III. proteins
IV. vitamins

A. I
B. III
C. I and IV
D. III and IV
37) C; Fats are absorbed into lacteals within the villi, NOT capillaries. Vitamins, meanwhile, are absorbed at the large intestine, not the small intestine. This makes I and IV true. II & III, carbohydrates and proteins, are indeed absorbed into the blood at the small intestine.
44. Which of the following locations within the circulatory system has the greatest blood pressure?

I. aorta, during diastole
II. lower leg, during systole
III. aorta, during systole
IV. upper leg, during diastole

A. I
B. II
C. III
D. IV
44) B; BP is greatest during systole, making I and IV impossible. The next factor to consider is the fact that the column of blood between the heart and the leg creates fluid pressure that must be ADDED to the normal BP. This means BP increases as you move downward from the heart. Statement II combines both these factors and thus is the correct statement.
What does it mean when we say a molecule is in the same "phase"?

Is solid sulfur usually found in the same phase?
Molecules of the same "phase" are:

1) in the same state (i.e., liquid, solid, or gas)
2) have the same chemical composition
and
3) are structurally homogenous

In its solid form, suflur forms S₈ and S₆ rings, among others. These meet the first two criteria, but not the third, so they are different "phases" of sulfur
∆Hfusion
The amount of energy in Joules required to go from solid to liquid or the energy that must be removed to go from liquid to solid. This describes the transition in both directions (i.e., melting and freezing)
∆Hvaporization
The amount of energy in Joules required to go from liquid to gas OR the energy that must be removed to go from gas to liquid. Again, it describes both evaporation and condensation
What is it called when a solid goes to a gas?
Sublimation
What is it called when a gas goes to a liquid?
Deposition
Volatile
evaporates easy
Has a low boiling point
What is the formula for,

Boiling Point Elevation?
Bp is elevated when a non-volatile solute is added according to:

∆T=Kbmi

Where Kb is a constant, m is molality (NOT molarity) and i is the number or ions formed per molecule
What is the formula for,

Freezing Point Depression?
Fp is depressed when a non-volatile solute is added according to:

∆T=Kfmi

Where Kf is a new constant, m is molality (NOT molarity) and i is the number or ions formed per molecule
If water is moving from compartment A to compartment B, what side has the higher osmotic pressure?
It is the side that will RECEIVE the water via osmosis that has the higher osmotic pressure

In other words, more solute means more osmotic pressure
What are the two formulas for osmotic pressure?
Π=iMRT

Π=pgha-pghb
...
Draw a heating curve for water
...
How do you calculate ∆Hfusion or ∆Hvaporization from a heating curve?
The change in q (x-axis) during the phase change
Once a phase change starts, how much heat is required to increase the temperature of a substance?
Once a phase change starts, all the energy goes into breaking inter molecular forces and none goes toward an increase in temperature
...
Draw a phase diagram
...
What do the lines on a phase diagram represent?
a point where the two phases on either side of the line are in equilibrium
What is critical temperature?
the temperature above which a gas cannot be liquefied, no matter how much pressure is applied.
What is Critical point?
Where there is no clear phase change boundries between a liquid and a gas. (beyond this point the substance is a supercritical fluid)
What critical pressure?
The critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature. Some examples are shown below.
What is a supercritical fluid
A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist.
For the majority of substances at their triple point, increasing temperature at constant pressure will result in which of the following transformations:

A) gas, liquid and solid to gas only
B) gas and liquid to solid only
C) gas, liquid and solid to liquid only
D) supercritical fluid to gas only
A
Solvent vs. Solute

Which is which?
This is NOT determined by which one is liquid or solid, or by any other factor. The one you have the most of is your solvent and the one you have the least of is your solute.
What is a Hydration Number?
the number of molecules of water with which an ion can combine in an aqueous solution of given concentration.
What are Colloids?
Colloids are NOT solutions

Colloids are solvents containing undissolved solute particles that are too small to be separated by filtration, but are much larger than the solute particles in a solution. Colloids scatter light, while true solutions do not. Examples of colloids include paint (a suspension of solid paint crystals in a solvent) and dust floating in air.
Molaity
moles solute/Kg solvent

Molarity (M) changes w/temperature, but molality (m) does not.
Mole Fraction
moles solute/total moles solution (solute + solvent)
mass percent
(mass solute/total mass solution)*100
ppm
(mass solute/total mass solution)*10⁶

One ppm is equivalent to 1 milligram of something per kilogram of something (mg/kg). NOT a measure of solute particles.

(for ppb multiply by 10⁹)
What is the measure of concentration,

Normality?
normality = # of equivalents/liter solution
What are the molecular processes involved in making a solution?
For a solution to form, the intermolecular forces between the solute particles must first be broken; then any intermolecular forces between the solvent particles must be broken (to make room for the solute). Finally, new intermolecular forces are formed between the solute particles and the solvent particles.

If the new intermoleuclar forces formed are greater (i.e., stronger, more stable) than the sum of the intermolecular forces that had to be broken, net energy is released and the solution is said to have a -∆Hsolution.

A negative Heat of Solution means that the dissolution process is exothermic and heat will be evolved. If the new intermolecular forces are not more stable than the old ones., the solution has a +∆Hsolution. A positive Heat of solution means that energy must be added to make the solute dissolve.
...
Vapor Pressure (VP) is the partial pressure of the gaseous form of a liquid that exists over that liquid when the liquid and gas phases are in equilibrium.

an indication of a liquid's evaporation rate

A substance with a high vapor pressure at normal temperatures is often referred to as volatile
How is vapor pressure affected by temperature?
The vapor pressure of any substance increases non-linearly with temperature
...
The atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and lift the liquid to form vapor bubbles inside the bulk of the substance. Bubble formation deeper in the liquid requires a higher pressure, and therefore higher temperature, because the fluid pressure increases above the atmospheric pressure as the depth increases.
What is Raoult's Law?
Used to calculate the partial VP of the solvent

Vapor Pressure w/ a non-Volatile Solute = (mole fraction of solvent)*(VP of the pure solvent)

Vapor pressure w/ a Volatile Solute = (mole fraction of solvent)*(VP solvent) + (mole fraction of solute)*(VP solute)
What is Henry's Law?
used to calculate the partial VP of the solute

Vapor Pressure of solute = (mole fraction of solute)*(Henry's Law Constant)
Saturated solution
the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a separate phase
Super-saturated solution
a solution that contains more of the dissolved material than could be dissolved by the solvent under the solubility amount. It can also refer to a vapor of a compound that has a higher (partial) pressure than the vapor pressure of that compound

Small particles (seeds) can trigger the separation of the dissolved material from the solvent or condensation of the vapor.
The Solubility Constant, Ksp
Exactly the same thing as Keq, Ka, and Kb.

Like all Ks, remember the following:

1)Leave out pure liquids and pure solids (this will make all Ksp equations one line)

2)Temperature is the only ting that changes Ksp

3)Ksp can only be measured for a saturated solution. This is because saturation is the point at which the dissolution reaction has reached equilibrium. In other words, it's just like all other Ks; you can't measure them anywhere other than equilibrium either.
Clarify the difference between "solubility" and the "solubility Constant."
The constant is generally independent of the presence of other species in the solvent
The solubility constant for AgBr in water is 5.2 x 10-

What is the aqueous solubility of AgBr?
Ksp= [Ag+][Br-]

5.2 x 10-13= x²

x= 7.2 x 10^-7
What is the Ion Product?
Also referred to as the "Solubility Product." Essentially, this is the same thing in relationship to Ksp as Q is in relationship to Keq.

Plug in the values for the actual concentrations of each species at some point other than equilibrium (i.e., for an unsaturated or supersaturates solution). If the product is greater than Ksp, you know a precipitate will form. If it is less than or equal to Ksp, then you know that no precipitate will form. If the ion product happens to be exactly equal to Ksp, then the solution must be exactly saturated (i.e., at equilibrium).
What are the steps in calculating solubility?
1) Write out the Ksp expression

2) Substitute into the expression the value given for Ksp

3) Substitute x into the equation for each ion, using 2x, 3x etc., if more than one mole of each ion is produced

4) Solve for x. Your answer, "x" is the "solubility" of that particular species (the solubility of parent molecules that broke apart)
What compounds are always soluble?
All compounds containing the following are SOLUBLE:

Nitrate
Ammonium
alkali metals (group IA)
What compounds are Insoluble?
All the compounds containing the following are INSOLUBLE:
(unless pared with something from the "always soluble" list)

Carbonate
Phosphate
Silver (Ag)
Mercury (Hg)
Lead (Pb)
Compared to Liquids and Solids, do gasses have stronger, weaker or equally strong intermolecular attractions?
Much Weaker
What does it mean that gasses are always miscible?
They all have the ability to mix homogeneously regardless of their polarity.
If temperature of a gas is increased, how will this effect the solubility of the gas?
It will become less soluble

Gas solubility is the exact opposite of solubility for liquids and solids. For gases, increased temperature decreases solubility and decreases temperature increases solubility
If temperature of a gas is decreased, how will this effect the solubility of the gas?
It will become more soluble

Gas solubility is the exact opposite of solubility for liquids and solids. For gases, increased temperature decreases solubility and decreases temperature increases solubility
How does increase the VP of a gas affect the solubility of that gas?
It will increase the solubility of the gas

This is why they pressurize soda pop cans with excess CO₂
What is the Ideal Gas Law?

What are it's assumptions?
1) Gas molecules have no volume
2) No intermolecular forces exist between gas molecules
3) All collisions are perfectly elastic
4) Average KE is exactly proportional to temperature
What are the standards of STP?
Unless specifically told otherwise, assume that all gases are ideal and start out at STP

At STP:

P=1atm
V=22.4
n=1 mole
R= 0.0821 L*atm/mol*K or 8.31 J/mol*K
T= 273 K (0° C)
How does STP differ from Standard Conditions?
Standard conditions usually indicates 25°C plus several other condtions

STP is at 0°C
What is the volume of a gas if its pressure is 2 atm, the temperature is 273 and there are 3 moles of gas total?
The pressure is double what it is at STP so the volume will be cut in half. At the same time, the molar amount is 3 items greater, which would increase volume by a factor of 3.

The volume will be 3/2, or 1.5 times what it normally is at STP
(22.4 x 1.5 = 33.6)
What situations will cause the greatest deviation between ideal gas behavior and real gas behavior?
a) when the temperature is extremely low
b) when the pressure is extremely high

Both scenarios result in the gas molecule being very close together. This is a deviation from ideal behavior, which assumes they are very far apart.
If there is more than one mole of gas when T=273, V=22.4 and P=atm, what is causing this deviation from ideal gas behavior?
IF PV/RT >1

it is due mostly to the molecular volume assumption
If there is less than one mole of gas when T=273, V=22.4 and P=atm, what is causing this deviation from ideal gas behavior?
IF PV/RT <1

it is due mostly to the intermolecular forces assumption
What is Dalton's Law of Partial Pressures?
Ptotal=P₁+P₂+P₃...

The important principle to conceptualize is that if we add more of Gas 1 (P₁) to an existing mixture of the three gases, we have increased the partial pressure of Gas 1 and the total pressure, but have had zero effect on the partial pressure of the other gases

Partial pressure is NOT similar to a mole or mass fraction. By adding more of Gas 1 we did decrease the mole fraction Gases, 2 and 3, but we did NOT decrease their partial pressures.
What is Effusion?
The diffusion of gas particles thru a pin hole. A pin hole is defined as a hole smaller than the average distance a gas molecule travels between collisions
What is Graham's Law?
E₁/E₂ = √(MW₂)/√(MW₁)

E₁ and E₂ can represent either the effusion rate or the diffusion rate of gases 1 and 2, respectively

Notice that the rate of effusion or diffusion is inversely to proportional to the molecular weight of the gas
Container A is a sealed reaction vessel containing 8.0 moles of hydrogen gas and 2.0 moles of chlorine gas. Container B is a sealed reaction vessel containing 2.0 moles of hydrogen gas and 8.0 moles of chlorine gas. If the gas mixtures in both containers behave as ideal gases, which of the following is true? (Note: Assume both containers are of equal volume and experience identical ambient temperatures.)

A) The pressure inside container B will be greater than the pressure inside container A.

B) The pressure inside container B will be less than the pressure inside container A.

C) The total number or moles of gas inside container A is greater than the total number of moles of gas inside container B

D) The pressure inside both containers will be exactly equal
D
Two students are working next to one another on the lab bench. Student A prepares a reaction in a beaker that evolves NO₂ gas. One meter away, Student B prepares a different reaction in a separate beaker that produces SO₂ gas. The students are unaware that these two gases mix in a highly exothermic reaction to form solid sulfur trioxide. At what point will the two gases meet and react?

A. 0.85 meters from the NO₂ beaker
B. 0.85 meters from the SO₂ beaker
C. 0.53 meters from the SO₂ beaker
D. 0.53 meters from the NO₂ beaker
D; This is an example of two gases diffusing through the air and combining to react with one another. This should remind you of the law for diffusion of gases, which states that the ratio of the velocities of two gases is proportional to the INVERSE of the ratio of the square root of their molar mass. This means that VNO2¬ over the VSO2¬ ¬is equal to the ratio of the square root of 64 (the MM of sulfur dioxide) over the square root of 46 (the MM of nitrogen dioxide). This simplifies to 8/7. We thus know that nitrogen dioxide travels faster, but only by a very small amount. Answers A and B have one or the other gas traveling many times faster, so these must be incorrect. Answers C and D show that they are very close to one another in speed, which is correct. The nitrogen dioxide is the fastest, so they should react closer to the sulfur dioxide beaker and further from the nitrogen dioxide beaker, or Answer D.¬
There are several copper nitrates that differ only in the oxidation number of copper. Each of them creates a blue solution when dissolved in water proportional to the umber of copper ions in the solution. Which or the following would produce a solution with the lightest blue color?

A. CuNO₃ ; Ksp=1x10⁻⁴
B. Cu(NO₃)₂ ; KSP=1x10⁻¹
C. Cu(NO₃)₃ ; KSP=1x10⁻⁶
D. All three would produce the same amount of blue color
A; IF all of the species form the same number of ions, then it is OK to compare their Ksps directly. This is because when you solve their Ksp equations for x, they'll all be raised to approximately the same power. If they form DIFFERENT numbers of ions, you must either calculate the actual solubility for each, OR you can usually use this shortcut: Raise each Ksp to the 1/x power, where x is the number of ions formed in solution. Do the math, and compare the resulting numbers, which will approximate the actual solubilities. In this case, Answer C appears to have the smallest Ksp, meaning it would be the least soluble and would thus produce the lightest blue color. However, when you use the shortcut above, you should get 1 x 10^-1.5 for Answer C and 1 x 10^-2 for Answer A, making A the best answer.
Which of the following nitrates is most soluble?

A. Fe(NO₃)₃ ; Ksp=1x10⁻¹²
B. Fe(NO₃)₂ ; Ksp=1x10⁻³
C. FeNO₃ ; Ksp=1x10⁻³
D. Fe(NO₂)₃ ; Ksp=1x10⁻³
The key says the answer is D however, that is not a nitrate granted it would be most soluble
A student begins a lab experiment by adding 725g of HCO₃⁻ to a beaker and then adding enough water to make 1 L of solution. Which of the following gives the molarty of the solution? (Note: Density of HCO₃=1.2g/mL)

A. 12m
B. 1.2m
C. 20m
D. 30m
D; There are approximately 12 moles of bicarbonate in 725g of bicarbonate. Molality is moles of solute/Kg of solvent, so we have the numerator. To get the Kg of solvent, first you must calculate the volume taken up by the solute. It is the total solution that is 1L; this is not the volume of the solvent alone. Dividing 725g by 1.2g/mL gives 600mL. This tells us that only 400mL of water was added to the beaker to make 1L of total solution. Finally, you must know that the density of water is 1g/mL. This gives us 12moles/.4Kg or 30 m, which is Answer D. This is a good time to point out that some MCAT answers may seem to be abnormally large, or small, or odd, or even unbelievable if you have any actual experience with the likely value of particular numbers in the lab. You couldn't really get 725g of bicarbonate dissolved into 400mL of water. However, you would NEVER need to know that because the MCAT would never expect you to have memorized the solubility of bicarbonate in water. Remember, it's all basic science principles!
Which of the following compounds is the least soluble in water?

A. K₂SO₄
B. (NH₄)₂CO₃
C. PbNO₃
D. CaSO₄
D; Right off the bat, we know that B and C are incorrect because they contain ammonium and nitrate, both of which are always soluble in ionic compounds. This leaves A and D. Sulfates are usually insoluble, except when group 1A elements. That makes D the best answer.

Always double check the periodic table!!
All of the following molecules produce a green solution proportional to the number of moles of copper ions dissolved in solution. Which of the following solutions will be the lightest shade of green?

A. CuCO₃
B. CuBr
C. CuO
D. CuPO₄
D; We know B is probably wrong because halide ionic compounds are usually soluble. Even if you don't know this, you're still OK. We know carbonates and sulfates are very insoluble. We also know that the greater the charges on the ions, the harder they will be to pull apart in solution. So, the CuSO4 (2+/2- ions) will be harder to pull apart than the CuBr (1+/1- ions). The copper phosphate has two magnitude three charges, which will definitely be the hardest, making D the best answer.
...
C; The one that will elute first is the one with the lowest boiling point. From the table, we can tell which species has the lowest boiling point by comparing their vapor pressures. A high vapor pressure means that species is closer to atmospheric pressure at that given temperature and will therefore boil sooner. Be careful with the scientific notation. The largest number in the table is for acetone, Answer C.
If reaction 1 is allowed to flow to completion and afterward the product mixture is heated, which of the following best describes the sequential change in pH?

MgCo₃(s) + H⁺(aq) ↔ Mg²⁺(aq) + HCO₃⁻(aq)

If heated, the solubility of magnesium carbonate decreases and results in:

Mg²⁺(aq) + 2HCO₃⁻ ↔ MgCO₃(s) + H₂O(g) + CO₂(g)

A. pH will gradually increase, then gradually decrease
B. pH will gradually increase, then increase even further
C. pH will gradually decrease, then gradually increase
D. pH will gradually increase, then remain constant
B; Whenever you are given a reaction and see hyrdrogen ions, or hydroxide ions, or are asked about pH, solving the problem is sure to have something to do with acidic or basic species being produced or consumed during the reaction. In this case, Reaction 1 consumes hydrogen ions, so pH will increase. That makes answer C impossible. Heating the products of Reaction 1, according to the passage, will cause Reaction 2 to occur. Reaction 2 may not immediately appear to consume an acidic species, but look carefully; it does. The bicarbonate ion still has one acidic hydrogen and it is being consumed. The results are a solid, a gas that is neither acidic or basic and water, which is neutral. This is definitely a net decrease in acidity, which correlates with a further increase in pH. Thus B is the best answer.
What do acid/bases taste like? Are they caustic? What does caustic mean?
Acids taste sour/tart and are usually caustic
Bases taste bitter, are slippery when wet and can be caustic
Caustic: Capable of burning, corroding, dissolving, or eating away by chemical action.
What is the Arrhenius definition of acids/bases?
Acids: Produce [H+] ions in solution
Bases: Produce [OH-] ions in solution
What is the Bronsted-Lowry definition of acids/bases?
Acids: Acids donate protons [H+]
Bases: Bases accept protons [H+]
What is the Lewis definition of acids/bases?

What are the most common Lewis Acids/Bases?
Lewis definition is the most general, and includes all the acids and bases in the Bronsted-Lowry definition and more.

Acids: Accept a pair of electrons
Bases: Donate a pair of electrons

Most common Lewis Acids: AlCl₃ and BF₃ (Molecules that have an incomplete octet of electrons around the central atom. They also include all simple cations except the alkali and the heavier alkaline earth metal cations.)
Most common Lewis Bases: NH₃, OH-, and anything else with an electron pair to donate.
What is an Acid/Conjugate Acid and a Base/Conjugate Base?
The conjugate base of an acid is the acid minus its hydrogen (HCl→Cl-)
The conjugate acid of a base is the base plus a hydrogen (Cl-→HCl)

In every reaction the acid has its conjugate base, and the base has its conjugate acid. Deciding which form is the conjugate simply depends upon in which direction you happen to be viewing the reaction.
What is an amphoteric substance?
A substance that can act as either an acid or a base (H₂O)
How do you calculate pH?

How does the ion concentration differ for two solutions, one with a pH=2 and the second with a pH=4?
pH=-log[H+]

There is a 100 fold increase from 2 to 4. There is a 10 fold increase in hydrogen ion concentration.
Be able to estimate pH for solutions that fall between the nice round numbers. The pH of a 1.0 x 10⁻⁴ solution is 4, but what is the pH of a 7.5 x 10⁻⁴ solution?
Any number greater than 1 will lower the pH value less than the number in the exponent. The higher the number the lower the decimal point.
1.2 x 10⁻⁵ = 4.9
9 x 10⁻⁵ = 4.05

7.5 x 10⁻⁴ = 3.12
What is the most defining characteristic for strong acids/bases?
They dissociate 100% in water (making them good electrolytes).
What are the strong acids? What is not a strong acid but often mistakenly labeled as such?
HI
HBr
HCl
HNO₃
HClO₄
HClO₃
H₂SO₄

HF is NOT a strong acid!
What are the strong bases?
NaOH
KOH
NH₂-
H-
Ca(OH)₂
Na₂O
CaO
What happens to acid dissociation as acid concentration increases? What happens to acid strength as acid concentration increases?
Acid dissociation decreases with increasing acid concentration. This is because the increasing hydrogen ion concentration in solution drives the dissociation equilibrium to the left.

Acid strength increases with acid concentration.
What is a polyprotic acid?
Acids with more than one acidic proton (i.e., H₂SO₄). The second proton is always MUCH LESS ACIDIC than the first; and can be ignored if the 1st and 2nd Ka are 10² or more apart (or 1st and 2nd pKa are 2 units apart).
How do you predict the acidity from a given structure?
Remember ARIO

Atom: Across the periodic table acidity increases with electronegativity (CH₄<NH₃<H₂O<HF). BUT, down the table acidity increases with size (HF<HCl<HBr<HI). You could make two arguments for why this is. The first reason has to do with the shorter (and stronger) H-F bond as compared to the larger hydrogen halides. The second has to do with the stability of the conjugate base. The fluoride anion, F(-) is a tiny and vicious little beast, with the smallest ionic radius of any other ion bearing a single negative charge. Its charge is therefore spread over a smaller volume than those of the larger halides, which is energetically unfavorable.

Resonance: A huge stabilizing factor for a conjugate base is if the negative charge can be delocalized through resonance. Can the lone pair of the conjugate base participate in resonance with an adjacent ∏ bond?

Induction: Electronegative atoms can draw negative charge toward themselves, which can lead to considerable stabilization of conjugate bases. EWGs can increase acidity of a nearby atom, which increases with electronegativity and decreases with increasing distance to the atom. (Electronegativity increases in the order F>Cl>Br>I)

Orbitals: Again, the acidity relates nicely to the stability of the conjugate base. And the stability of the conjugate base depends on how well it can accomodate its newfound pair of electrons. In an effect akin to electronegativity, the more s character in the orbital, the closer the electrons will be to the nucleus, and the lower in energy (= stable! ) they will be. (sp³ (25% s) < sp² (33% s) < sp (50% s))
What is more acidic, chlorous acid or percholoric acid? Why?
Perchloric acid is more acidic. The electronegative oxygens draw electrons to one side of the bond, increasing polarity. The oxygens in the conjugate of a oxyacid can share the negative charge spreading it over a larger area and stabilizing the conjugate base. In similar oxyacids, the molecule with the most oxygens makes the strongest acid.
What are hydrides and are they basic or acidic?
Hydrides are binary compounds containing hydrogen.

Basic hydrides are on the left of the periodic table and acidic hydrides are on the right. The line between groups V & VI is the approximate dividing line.
How do you calculate all the equilibrium constants (Keq, Ka, Kb, or Ksp).
To calculate put the concentration of the products over the reactants and omit pure (l) and (s).
Ka=[H⁺][A⁻]/[HA] → (HA+H₂O→H₃O⁺+A⁻)
Kb=[OH⁻][HA]/[A⁻] → (A⁻+H₂O→OH⁻+HA)
What does a large Ka or small pKa mean? A large Kb or small pKb?
Think of it just as you do with Keq. A large Ka, or small pKa, indicates that at equilibrium there are far more products than reactants. For an acid dissociation this would mean a lot of dissociation (i.e., a lot of H⁺ formed) and thus a very strong acid. Similarly, a large Kb, or a small pKb, indicates a very strong base.
How do you calculate Kw? Demonstrate using the short equation and how that equation is found.
Kw=[H₃O⁺][OH⁻]=Ka*Kb=10⁻¹⁴

H₂O+H₂O→H₃O⁺+OH⁻
Kw=[H⁺][OH⁻]
([H⁺][A⁻]/[HA])x([OH⁻][HA]/[A⁻] )→[H⁺][OH⁻]=Kw
Ka*Kb=Kw
How do you calculate pKw?
Kw=[H⁺][OH⁻]
log(AB)=log(A) + log(B)
pKw=pH+pOH
pH+pOH=14
pKw=14

Kw=KaKb
pKw=pKa+pKb
pKa+pKb=14
pKw=14
How do you calculate the pH or pOH of a strong acid or base? What are you assuming to make this calculation?
pH=-log[strong acid]
pOH=-log[strong base]

You must assume that the strong acid/base completely dissociates in water.
How do you calculate the pH of a weak acid?
1. Write out the equilibrium equation (HA↔H⁺+A⁻)
2. Use x to represent the concentration of each of the two products (or 2x, 3x, etc. depending on the coefficients in the balanced equation).
3. Use "[HA]-x" for the concentration of the original acid.
4. If this results in a quadratic equation, assume that x is much smaller than [HA] (#3 above) and omit it.
5. Solve for x
6. Use -log[H⁺] (i.e., -log[x] to find the pH)
How do you predict the acidity of salt solutions? Is NH₄NO₃ acidic or basic?
To determine if NH₄NO₃ will form an acidic, neutral, or basic solution, look at the conjugate acid/base associated with each species. In this case, that is NH₃ and HNO₃. Because NH₃ is a weak base and HNO₃ is a strong acid, the solution will be acidic. If the base was strong and the acid was weak, the solution would be basic. Finally, if both the acid and the base are considered "strong" the solution will be neutral.
If a question states: "A strong base is titrated with a strong acid," which one is being added dropwise and which one is in the beaker? Which solution is referred to as the titrant? Which solution is referred to as the anylate?
The strong acid is being added stepwise (titrant). The strong base is in the beaker (anylate).

The titrant is the solution added stepwise.

The anylate is the solution in the beaker.
When dealing with titration, what does one "equivalent" mean? How many equivalents of base can be neutralized by one equivalent of H₂SO₄.
One equivalent is the amount of acid or base necessary to produce or consume one mole of [H+] ions.

2 equivalents of base can be consumed by one equivalent of H₂SO₄.
In a titration of a SA w/ SB or a SB w/ SA, where is the equivalence point (stoichiometric point) and what does it mean?
Equivalence Point (Stoichiometric Point): The midpoint of the nearly vertical section of the graph. At this point [titrant]=[anylate].

For example, for a solution of NaOH being titrated with HCl, at the equivalence point [HCl]=[NaOH]. Put another way, the moles of HCl in the beaker=the moles of NaOH in the beaker. Because HCl and NaOH are both considered "strong" (dissociate 100% in water), they will both produce the same amount of ions per mole. Thus, for titrations involving a SA and a SB, [H⁺]=[OH⁻] at the equivalence point (THIS IS NOT TRUE IF A WA OR WB IS INVOLVED). By definition if these two are equal, pH=7 at the equivalence point.
In a titration of a WA w/ SB or WB w/ SA, where is the equivalence point and what does it mean?
Equivalence Point: The midpoint of the nearly vertical section of the graph. At the point the [titrant]=[anylate]. However, because the acid and base are not both "strong" (dissociate 100% in water) the [H⁺] does NOT equal [OH⁻]. This also tells us that the pH does not equal 7.
At the equivalence point where is the pH for the following situations?

1) SA w/ WB
2) WA w/ SB
3) SA w/ SB
4) WA w/ WB
1) SA w/ WB: pH<7
2) WA w/ SB: pH>7
3) SA w/ SB: pH=7
4) WA w/ WB: pH=7 (these titrations are rarely attempted)
What are half-equivalence points? Where are they found on a graph? In what situations will there be a half-equivalence point?
Half-equivalence point: The midpoint of the nearly horizontal section of the graph. Here the pH=pKa. We can also say that [HA]=[A⁻] at the half-equivalence point. HA will continue to be deprotonated until at the equivalence point the solution contains 100% A⁻ and 0% HA.

This is not true of a titration involving a strong acid and strong base because they both dissociate 100%. Therefore, by definition, almost immediately after adding HA 100% has been changed to A⁻. Therefore, SA/SB titrations DO NOT have half-equivalence points.
What is an indicator in titrations?
Indicators are weak acids that change color as they dissociate from HA into H⁺ and A⁻. To set up a titration, you MUST know beforehand the approximate pH of your equivalence point; you then select an indicator that is supposed to "go off" at that approximate pH. The dissociation of the indicator and the acid/base reaction we are analyzing run simultaneously in the same beaker but are otherwise unrelated.
What is an end-point and how does it compare to the equivalence point?
The End Point is simply the point when the indicator causes the color change. The equivalence point is where [titrant]=[anylate]. There is NO causal relationship whatsoever between the solution reaching the equivalence point and the indicator changing color (i.e., the endpoint). The extent to which they do or do not correlate depends entirely on the indicator chosen.
Why does pH=pKa at the half-equivalence point? What equation describes this?
The half-equivalence point is the point where exactly one half of the acid has been neutralized by the base, or the concentration of the acid is equal to the concentration of its conjugate base [HA]=[A⁻].

Since Ka=[H⁺][A⁻]/[HA]
-log(Ka)=-log[H+]-log([A-]/[HA])
pKa=pH-log([A-]/[HA])

Since [HA]=[A⁻], the second part of the equation equals zero (log(1)=0) and the pKa=pH
Where is a buffer found on a titration curve? What is a buffer? What equation describes how a buffer works? How do you make a buffer?
The nearly horizontal area surrounding the half-equivalence point is a buffer. Adding a relatively large amount of titrant at this point in the titration will have little affect on pH.

pH=pKa+log[A-]/[HA]

1) Start with an acid whose pKa is as close as possible to the pH at which you want to buffer.
2) Mix equal amounts of that acid with its conjugate base
3) Make alot of it, so that the amount of buffer is much greater than the acid or base being buffered.
What are some clues to help recognize buffer problems?
1) Watch for equimolar amounts. Remember that to create a buffer you start with equal amounts of a weak acid and its conjugate base, or a weak base and its conjugate acid.
2) Watch for conjugates. To be a buffer, the two equimolar substances must be conjugates of each other, such as: NH₃ and NH₄⁺, CH₃COO⁻ and CH₃COOH, or HCO₃⁻ and CO₃²⁻.
3) Watch for WEAK acids or bases. The equimolar pair MUST be a WEAK base or a WEAK acid and its conjugate. Strong acid or strong base conjugate base pairs DO NOT form buffers.
4) Watch for resistance to pH change. Any time an acid or base is added to a solution and the pH does NOT change "very much," or "changes slightly," this should be a dead giveaway that the solution was a buffer.
5) Watch for the half-equivalence point. Remember that ONLY solutions of weak conjugate acid/base pairs have a buffer region, and therefore they are the only solutions that have a half-equivalence point.
6) Watch for pH=pKa. Many students memorize this principle, but fail to recognize that what it is really saying is that pH=pKa at the midpoint of the BUFFER region. This is another unmistakable clue that you are dealing with a buffer.
7) Watch for the ratio of [HA]/[A-] or [A-]/[HA]. One particular problem asks about the ratio of an acid to its conjugate base. Those who recognize it as a buffer problem usually answer it correctly.
What is a Redox reaction?
Any reaction where electrons are transferred from one atom to another. The atom that loses an electron is oxidized and the atom that gains an electron is reduced.
What do you need to do to calculate which atom is losing electrons and which atom is gaining electrons?

Fe(s) + H₂O(l) → H₂(g) + FeO(s)
In this reaction iron loses two electrons and two hydrogens each gain one electron. To recognize this, you must be able to calculate the oxidation state of each species.
What is an oxidation state and what are the common oxidation states of the following atoms:

1) Any elemental atom
2) Fluorine
3) Hydrogen
4) Hydrogen w/ a metal
5) Oxygen (except peroxides)
6) Alkali metals
7) Alkaline earth metals
8) Group V
9) Group VI
10) Group VII
The oxidation state is the apparent charge that an atom takes on while in a molecule. The sum of the oxidation states for all of the atoms in a molecule must equal the charge on that molecule, or equal zero if the molecule is neutral.

1) Any elemental atom: 0
2) Fluorine: -1
3) Hydrogen: +1
4) Hydrogen w/ a metal: -1
5) Oxygen (except peroxides): -2
6) Alkali metals: +1
7) Alkaline earth metals: +2
8) Group V: -3
9) Group VI: -2
10) Group VII: -1
With redox reactions, what is the electrical potential and how are they calculated?
Because redox reactions involve the movement of electrons from "high" to "low" concentration, a potential difference exists between the high and low concentration species. This is no different than a battery, where electrons are more concentrated at the negative terminal than they are at the positive terminal. To know the degree to which each species "wants electrons" or "wants to be reduced" we rate all species relative to the potential of two hydrogen ions to gain two electrons to form H₂(g). We define this as E⁰=0.00V.

2H⁺ + 2e⁻ → H₂ E⁰=0.00V
A species with a positive E⁰ is MORE likely to gain electrons (i.e., be reduced) than are hydrogen ions. A species with a negative E⁰ has NO tendency whatsoever to gain electrons and instead is likely to lose electrons (i.e., be oxidized).
How do you use reduction potential tables (Half-Reaction potentials)?

What do you do with stoichiometry? If I have two moles do I multiply the potential?

What are the potentials that are given (reduction/oxidation)? What does a positive/negative number mean?
1) Half-reactions never happen alone; they must be paired.

2) Add/Reverse the half-reactions as necessary to find the potential for a complete redox RXN.

3) DO NOT USE STOICHIOMETRY!!!! (i.e., one mole of Cu²⁺ has the same reduction potential as two moles.)

4) ONLY reduction potentials are given because oxidation potentials are just the reverse RXN w/ the opposite sign.

5) Positive number means it is reduced (gain electrons), negative means it is oxidized (loses electrons)

6) Something with a high reduction potential "wants" to be reduced or "reduces easily". Something with a high oxidation potential "wants" to be oxidized.
Would you expect a strong oxidizing agent to have a high or low reduction potential?
It would have a high reduction potential. An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction. The oxidizing agent is "reduced" by taking electrons onto itself and the reactant is "oxidized" by having its electrons taken away.
What is a galvanic cell and describe how they work. What is the sign of the cathode/anode and what takes place at the cathode/anode (reduction or oxidation)?
.
1) RED CAT and AN OX - Remember Reduction always occurs at the cathode and oxidation always occurs at the anode.

2) Anode = (-)
3) Cathode = (+)

4) At the anode, electrons leave the metal (Zn) as the zinc is oxidized. The ions (Zn²⁺) then dissolve into the solution.

5) At the cathode, Cu²⁺ ions gain two electrons and are reduced to form solid copper.

6) At the salt bridge positive ions dissolve into the copper solution to neutralize the buildup of negative charge. Negative ions dissolve into the zinc solution to neutralize the buildup of positive charge from the zinc.
What is a concentration cell. How does a concentration cell work? How do you calculate the voltage?
.
1) A concentration cell is a special type of galvanic cell. The same electrodes and solution are used in both beakers. (If both concentrations were equal E⁰ would be 0.00V).

2) The two concentrations are different.

3) Electrons flow from the electrode in the [low] to the electrode in the [high]. This causes ions to form from the metal in the low concentration and ions to form the metal in the high concentration.

4) The nernst equation is used to calculate the cell potential based off of the E⁰ of the species and the two concentrations.

E=E⁰-(0.06/n)*log[lower]/[higher]

n=number of electrons used each time the reaction occurs

5) RED CAT and AN OX - Remember Reduction always occurs at the cathode and oxidation always occurs at the anode.
Anode = (-)
Cathode = (+)
The anode is in the lower concentration solution and the cathode is in the higher concentration solution.
What is an electrolytic cell. How does it work?
A galvanic cell that has been attached to a power source that forces the current to flow in the opposite direction.

1) It has a negative potential
2) It is non-spontaneous
3) The signs of the cathode and anode are reversed.
4) RED CAT and AN OX
Cathode = (-)
Anode = (+)
5) Electrons still move from the Anode to the Cathode.
How do we create a relationship between free energy and chemical energy?
∆G=-nFE⁰

+E⁰=-∆G=spontaneous reaction

F=Faradays Constant=the charge on on mole of electrons. The charge of one electron = 1.6 x 10⁻¹⁹C.

Therefore F=(1.6 x 10⁻¹⁹)*(6.02 x 10²³) = 9.6x10⁴C/mol
What is the relationship between a Faraday and a Farad?
There is none. A Faraday is an obsolete unit of charge equal to the charge on one mole of electrons (1.6x10⁻¹⁹)x(6.02x10²³)=9.6x10⁴
Faradays constant = 1 Faraday. The Faraday has since been replaced by the Coulomb.

A Farad is a unit of capacitance. It is a "summary" unit similar to a NEwton. Just as we can say 1 Newton instead of saying 1 Kg*m/s², we can say 1 Farad instead of saying 1 C²*s²/m²*kg. A Farad is the amount of capacitance necessary to hold 1 C of charge on a capacitor with a potential difference of 1 Volt.
9. A student is given a 100mL sample of NaOH of unknown concentration and asked to establish its molarity via titration. After adding 50mL of H₂SO₄ dropwise into the unknown, the solution turned pink. If it is assumed that H₂SO₄ dissociates 100% which of the following gives the molarity of the NaOH solution? (Note: density of H₂SO₄=0.9 g/cm³)

A. 2.0 M
B. 3.5 M
C. 4.6 M
D. 9.2 M
9) D; Titration problems such as these do show up on the MCAT, although they are often simplified to reduce the calculations. The reason we include one of these is because it is a good test of your understanding of titrations. You cannot usually solve this problem unless you understand conceptually how a titration works. We added 50mL of sulfuric acid. Multiplying this by the density gives us the grams of sulfuric acid added, about 45g. We convert this into moles and get 0.46 moles. However, sulfuric acid is diprotic and we were told to assume 100% dissociation (meaning both protons will come off), thus it will only take half as many moles of sulfuric acid to consume all the moles of base. Thus we know that there must have been .92 moles of NaOH in the solution. We now just divide this by the liters of solution to get the molarity of the NaOH; 0.92moles/0.1L = 9.2M
17. K₂CO₃(s) dissolves readily in water to form a colorless solution. If blue litmus paper is placed into this solution it will:

A. remain blue, because potassium carbonate is neutral
B. remain blue, because carbonate reacts with water to form bicarbonate and hydroxide ions
C. turn red, because carbonate reacts with water to form bicarbonate and hydrogen ions
D. turn red, because potassium will react with water to form an acid salt
17) B; Be careful here, you may have memorized that in the blood carbon dioxide reacts with water to form bicarbonate and hydrogen ions. But, this is not carbon dioxide, it is carbonate, CO32-. This is a base that will abstract a proton from water forming bicarbonate and leaving OH- ions. The result is a basic solution, whereas the result of the first reaction is an acidic solution. Blue litmus paper turns red in acid, but stays blue in base, so B is the best answer.
19. A student creates two electrolytic cells, one containing a salt solution of CuSO₄ ions and the other containing a salt solution of FeSO₄ ions. Using a voltmeter, it is determined that an external voltage of 2.5V is required to force a reaction at the cathode in the CuSO₄ solution and 2.9V is required to force a reaction at the cathode in the FeSO₄ solution. Which of the following conclusions is justifiable?

A. Cu²⁺ has a higher reduction potential than Fe²⁺
B. Fe²⁺ has a higher reduction potential than Cu²⁺
C. Cu²⁺ is a better reduction agent than Fe²⁺
D. Fe²⁺ is a better oxidizing agent than Cu²⁺
19) A; From the question we know that the reaction is occurring at the cathode and must therefore be reduction. The metal ions are being reduced to their ground state metals, Cu(s) and Fe(s). Because the iron solution requires MORE voltage to force reduction, iron must have the lower reduction potential. Cu2+ must then have the higher reduction potential. This makes A true. B is false because it is the opposite of A. If Cu2+ is more easily reduced, this also means it will more easily oxidize another species to accomplish this, making it the better oxidizing agent. Answers C and D confuse these two facts.
27. Reaction 1 is one of several steps carried out during the industrial manufacture of HCl. Instead of a Galvanic cell, however, an electrolytic cell is utilized. Which of the following gives the location of the formation of chloride and potassium ions during the industrial application of Reaction 1?

2K(s) + Cl₂(g) → 2K⁺(aq) + 2Cl⁻(aq)

A. Cl ions at the anode and K ions at the cathode
B. Cl ions at the cathode and K ions at the anode
C. Both ions at the cathode
D. Both ions at the anode
27) B; The formation of Cl- ions requires the reduction of diatomic chlorine and reduction always occurs at the cathode, thus the chlorine ions must be formed at the cathode. The formation of the potassium ions requires oxidation, and therefore must occur at the anode.
31. For a spontaneous, exothermic reaction, which of the following would be expected?

A. K>∆G
B. K<∆G
C. K<1
D. K=1
31) A; ΔG=-RTlnK Recall that when K=1, Gibb's free energy is equal to zero. This makes answer C impossible. If K were less than one, this would indicate an unfavorable equilibrium resulting in mostly reactants and very few products. This would not be expected for a favorable reaction releasing a lot of heat. Answer A, however, makes sense because Gibb's free energy should be negative and K should be large and positive, which would indeed make K greater than ∆G.
What is the difference between longitudinal waves and sound waves?
Longitudinal - compressional waves/mechanical waves
e.g., sound and earthquakes

Transerve
e.g., light, wave on a string
What is the period of a wave?
The period of a wave is the time for a particle on a medium to make one complete vibrational cycle
How is intensity of a wave related to amplitude and frequency?
Intensity is directly proportional to the amplitude squared and the frequency squared
How dose the Decibel system work?
It is a log scale

10-fold increase in sound intensity are represented by 10.0 unit increases on the decibel scale. For example a sound 10 times more intense is rated as 10 decibels higher, a sound 100 times more intense is rated as 20 decibels higher and a sound 1000 times more intense is rated as 30 decibels higher
What is the formula for Intensity in Decibels?
Intensity in Decibels = 10*log(I/I₀)

Where I is the intensity of the sound wave in W/m² and I₀ is the threshold of human hearing (1x10⁻¹² W/m²; always given)
At a soccer match, the sound level suddenly rises from 20 decibels to 60 decibels. How much louder is the sound at the end of this increase?
10,000 times louder
What is the wave speed formula?
V=wave length x frequency
What are the 3 cardinal wave rules?
1) Wave speed (velocity) is determined by the medium
2) frequency never changes from medium to medium
3) Wavelength does change from medium to medium
How is velocity of a wave on a string related to its mass/unit length (density) and elasticity o the string?
Velocity of a wave on a string is inversely proportional to the mass/unit length or density of the string (if tension is equal) and directly proportional to the elasticity of the string
How is velocity of a sound wave related to density of the medium?
velocity of a sound wave is directly proportional to the density of the medium.

(technically, this is NOT true - the density of the medium actually slows down the wave. However, the more dense mediums also have higher bulk moduli which cause the wave to reverberate through the medium more quickly. The bulk modules has more impact on wave velocity than the density, so the net effect is that sound, and other compressional waves, travel faster in more dense mediums).
How can you find the beat frequency?
Fbeat= abousolute value of (f₁-f₂)
What will two waves add to if they are: 180° out of phase? 360° out of phase? 270° out of phase
180° = 0
360° = 2x
270° = same
What are the Formulas for the Doppler Effect?
∆f/fs = v/c
∆λ/λ = v/c

Remember:

1) v is relative velocity, not the velocity of either object.

2) the variable c is either 3x10⁸ or 340 m/s

3) the answer is the change in the frequency or wavelength (often NOT what is asked for). This value must be added or subtracted from the initial value to get the actual value due to the Doppler effect
What will be the change in frequency due to the Doppler Effect when the source and observer are traveling at identical velocities?
There will be no change
What are two common color shifts due to he Doppler effect?
White light can shift blue if Doppler causes an increase in frequency and red if Doppler causes a decrease in frequency

(think about this, its not too hard to reason out)
Sound-proofing materials are used to isolate audiovisual production rooms and prevent the passage of sound into or out of he designated room. Rooms that are NOT constructed to such standards often allow the passage of sound through a wall because:

A) sound waves can pass through microscopic pores in natural building materials
B) sound waves can pass through solid object without losing amplitude or velocity
C) sound waves pass through solid objects, losing some amplitude, but maintain a constant velocity
D) sound waves pass through solid objects, exiting the solid with the same velocity that had just prior to striking the solid.
D
What is the harmonics formula for a pipe open at both ends or a string fixed at both ends

(i.e., both Node or Antinode)
L=nλ/2

Gives all harmonics n=1,2,3...

May be more useful to rearrange as

λ = 2L/n
What is the harmonics formula for a pipe open at one end only or string fixed at one end only

(i.e., one node and one antinode)
L=nλ/4

Gives only the odd harmonics; n=1,3,5...

May be more useful to rearrange as λ=4L/n
What are he general Rules of harmonics?
Each harmonic will have its own new frequency

Each harmonic will have one more antinode than the previous

Frequency is always n*fundamental frequency (e.g., if the first harmonic is exactly 200 Hz, the 2nd is 400 Hz, the 3rd is 600 Hz, etc.)

The 2nd harmonic is unique, because this is the only time L=λ
(for both Node or Antinode situations; i.e., open pipe or closed string)
A student blows into a pipe open at both ends and creates a fundamental frequency. He then increases his pitch gradually until he reaches the 2nd and 3rd harmonics. While the 3rd harmonic is resonating, the student puts his hand over one end of the pipe. To attain the 3rd harmonic for the new system, the student must:

A) increase the frequency of the sound
B) decrease the frequency of the sound
C) maintain a constant frequency
D) decrease the wavelength of the sound
The 3rd harmonic for this pipe will have three nodes and three anti-nodes. When the student places his hand over the pipe, he creates a pipe open at one end and closed at the other. The third harmonic for this new system will have only two nodes and two anti-nodes. By drawing these harmonics on the same length of pipe we can see that the 3rd harmonic in the second case is clearly of lower frequency. Answer B is therefore correct. You could also solve λ=2L/n and λ=4L/n, for the first and second case, respectively. This shows that in the second case the wavelength is higher and therefore the frequency must be lower.
What is the formula for the index of refraction?

What can be inferred about a material with an index of refraction of A) 0.9 and B) 1.5?
n=c/v

b is more dense
...
Draw the electromagnetic spectrum from gamma rays to radio waves
...
What is a mnemonic to remember the order of visible light?
ROY G BIV
What is the Formula for Snell's Law
n₁sinӨ₁=n₂sinӨ₂
What happens to the frequency and wavelength of light when it crosses into a new medium?
Wavelength shortens

Frequency is unchanged
If light hits a denser medium at an angle, will it bend toward the normal line or away from it?

When it goes from a denser to a less dense medium which way will it bend?
less dense to more dense: Toward it

more dense to less dens: Away from it
What does a converging lens produce (aka, convex, positive)?
Usually produces a positive, real, inverted image.

When the object is inside the focal point it produces a negative, virtual, upright image.
What does a Diverging lens produce (aka, concave, negative)?
always produces a negative, virtual, upright image
Where does the image have to be in order to be at the focal point?
Very distant

behavior of light rays at lenses and mirrors assumes parallels light rays, which is approximated by light emanating form a very distant object.

As the object approaches the lens, the image will no longer be exactly at the focal point.

The MCAT has tested this assumption multiple times
What is the formula for the focal point of a mirror?
F=1/2r
what is the formula for the focal point of thin lenses?
1/f=1/di+1/d₀
What is the formula for magnification?
M= -di/d₀=hi/h₀

If you get a negative number for the magnification, M, that tells you the image is inverted
What are the four lens/mirror rules?
1) object distances (d₀) are always (+)

2) image distances (di) or focal point distances (f) are (+) if they are on the same side as the observer and (-) if they are on the opposite side

3) The observer and object are on the same side for a mirror and on opposite sides for a lens

4) PRI / NVU: "Positive, Real, Inverted" and "Negative, Virtual, Upright" always stay together! You only need to establish one characteristic and you automatically know the other two!
What is the difference between Near-Sighted and Far-Sighted?
Near-Sighted - Abe to focus clearly on close objects, but not on distant objects (the image is formed in front of the retina)

Far-Sighted - able to focus clearly on distant objects, but not on close objects (the image is formed behind the retina)
Why does the image move in front of or behind the retina for near- or far-sighted people?
Near-sighted - the lens is too convex

Far-sighted - the lens is too flat
What is the formula for optical power?
P=1/f
What is the formula for the magnification of two lens systems (e.g., binocular, telescopes, etc)?
M = m₁m₂
What is the formula for optical power for two lens systems (e.g., binocular, telescopes, etc)?
P = p₁+p₂
An object is viewed through a convex lens. Assuming the object is outside the focal distance, the image formed will be:

A) on the same side of the lens as the observer and virtual
B) on the same side of the lens as the observer and real
C) on the opposite side of the lens as the observer and virtual
D) on the opposite side of the lens as the observer and real
A converging lens can only form an NVU image if the object is within the focal distance. We are told it is not, so we know the image must be positive, real and inverted. Positive means it is on the same side as the observer, which makes answer B correct. The image must also be inverted
What is the general Pressure Formula?

What are all the different units?
P=F/A

Units= Pascals, mmHg, atm or Torr

The SI unit for pressure is the pascal (Pa), equal to one newton per square meter
How do you convert between pascals, mmHg and Torr in any order
1 atm = 1.01325 ×105 Pa
1 atm = 760 Torr
1 atm = 760 mmHg
Fluid Pressure Formula
P=pgh

p = density in kg/m3 g = acceleration due to gravity (9.8 m/s2) h = depth of liquid in m

Can be thought of as the average force of molecular collisions per unit area or as the wight of the column of liquid above a submerged object
What is gauge pressure
is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure. Negative signs are usually omitted
Specific Gravity
SG=D(substance)/D(H₂O)

density of water = 1g/ml

For object floating in liquids, the fraction submerged = the ratio of the density of the object to the density of the liquid. It is also given by the ratio of the specific gravities
A ball is 3/4 submerged in a liquid with a density of 2 g/cm₃. What is the specific gravity of the liquid and the density of the ball?
density of the ball = 1.5g/ml
SG=3/4

(check answer)
Archimedes' Principle
Any submerged or floating object displaces an amount of liquid exactly equal to its own volume, or to the volume of whatever fraction of the object is submerged. The weight of that amount of liquid, in newtons, is exactly equal to the buoyant force pushing up on the object
What is the equations for the buoyant force?
F(buoyant)=pvg

THE BUOYANT FORCE IS ALWAYS EXACTLY EQUAL TO THE WEIGHT OF THE AMOUNT OF FLUID DISPLACED
What causes the buoyant force
Buoyant force is caused by gravity acting on the fluid. It has its origin in the pressure difference occurring between the top and bottom of the immersed object, a difference that always exists when pressure varies with depth

an object submerged in the fluid experiences greater pressure at the bottom than at the top. This difference in pressure results in a net force that tends to accelerate an object upwards
What is apparent weight? and what does it tell us?
The apparent weight of a submerged object is the actual weight minus the buoyant force

The difference between the actual wight and the apparent weight gives you (1) the buoyant force and (2) the weight of that volume of liquid
What is the equation for Cardiac output?
Cardiac Output = stroke volume x heart rate
What is the formula for flow rate?
Q=AV

Note: this is only true of a closed system (no intake or outflow)

Biology connection: this formula is often used to describe fluid flow in the cardiovascular system. The variable A is the cross-sectional area of the blood or lymph vessel and V is velocity.
What is Bernoulli's Equation?
K=P + pgh = 1/2pv²

this demonstrates the Law of Conservation of Energy: the random kinetic energy of the fluid molecules is given by P; the gravitational potential energy of the fluid is given by pgh; the energy due to moving fluid molecules is given by 1/2pv² (any volume of fluid has mass, so this is just like calculating KE for a solid mass with some velocity).

THE SUM OF THESE THREE FORMS OF ENERGY IN AN IDEAL FLUID IS ALWAYS A CONSTANT (K). ENERGY IS TRANSFERRED FORM ONE FORM TO THE OTHER BUT THE SUM WILL NEVER CHANGE.

When the fluid of a pipe increases in speed as it enters a narrow section, its temperature drops. This is due to the conversion of energy from the random kinetic energy of the fluid molecules (the P term) into translation kinetic energy (the 1/2pv₂ term).
What is an equation that gives the velocity of water exiting a spigot?
v=square-root(2gh)
a 20 kg block of unknown density has an apparent weight of 150 Newtons when fully submerged in a liquid with a density of 8 g/cm³. What is the density of the unknown object?
32 g/cm³

See altius manual page 186 for more help
What is Surface Tension
The intensity of intermolecular forces per unit length at the surface of a liquid
What is Cohesive ?
like molecules sticking together, being mutually attractive. This is an intrinsic property of a substance that is caused by the shape and structure of its molecules which makes the distribution of orbiting electrons irregular when molecules get close to one another, creating electrical attraction that can maintain a macroscopic structure such as a water drop.

Water, for example, is strongly cohesive as each molecule may make four hydrogen bonds to other water molecules in a tetrahedral configuration. This results in a relatively strong Coulomb force between molecules. Van der Waals gases such as methane, however, have weak cohesion due only to Van der Waals forces that operate by induced polarity in non-polar molecules

Mercury in a glass flask is a good example of the effects of the ratio between cohesive and adhesive forces. Because of its high cohesion and low adhesion to the glass, mercury does not spread out to cover the top of the flask, and if enough is placed in the flask to cover the bottom, it exhibits a strongly convex meniscus, where the meniscus of water is concave. Mercury will not wet the glass, unlike water and many other liquids,[1] and if the glass is tipped, it will 'roll' around inside.
What is adhesive forces?
Adhesive forces are the attractive forces between unlike molecules. They are caused by forces acting between two substances, such as mechanical forces (sticking together) and electrostatic forces (attraction due to opposing charges). In the case of a liquid wetting agent, adhesion causes the liquid to cling to the surface on which it rests. When water is poured on clean glass, it tends to spread, forming a thin, uniform film over the glasses surface. This is because the adhesive forces between water and glass are strong enough to pull the water molecules out of their spherical formation and hold them against the surface of the glass, thus avoiding the repulsion between like molecules.
...
Which force is greatert in a concave-up meniscus:

Choesive or Adhesive forces?

Concave-down miniscus?
How does this cohesive force create both a concave up and concave down surface then? The answer is in its relationship to the adhesive forces between the water molecules and the container's surface. When the cohesive force of the liquid is stronger than the adhesive force of the liquid to the wall, the liquid concaves down in order to reduce contact with the surface of the wall. When the adhesive force of the liquid to the wall is stronger than the cohesive force of the liquid, the liquid is more attracted to the wall than its neighbors, causing the upward concavity
What does a positive charge indicate?
Mealy the lack of electrons relative to another location

NOT the location of particles with a positive charge!
Charge is quatized according to the charge of and e⁻

What is that charge?
1.6x10⁻¹⁹
Which way does current flow?
opposite to the direction of electron flow
From (+) to (-)

Electron from from (-) to (+)
Which way does current flow in a batter?

Which way do the electrons flow in that same batter?
Current :From (+) to (-)

Electron: From (-) to (+)
A very small parallel plate capacitor is charged until it bears amaximum charge of 8.0x10⁻¹⁹ C. A change in the dielectric causes the charge to decrease slightly. Which of the following gives the new charge?

A) 1.9x10⁻¹⁹ C
B) 4.8x10⁻¹⁹ C
C) 4.0x10⁻¹⁹ C
D) 7.9x10⁻¹⁹ C
In the case of the "micro" capacitor, the charge on the capacitor is due to exactly five electrons. Recall that charge is quantized and that the charge on one electron is 1.6x10⁻¹⁹ C. The charge can never decrease or increase by a number that is not a multiple of 1.6x10⁻¹⁹ C. The charge can never decrease or increase by a number that is not a multiple of 1.6x10⁻¹⁹ C.

Answer B is the only answer that fits this criterion
How do you draw electric field lines?
Always drawn with their tails a the positive charge and pointing toward the negative charge.
Do field lines best approximate electron flow or current flow?
Current flow:

(+) to (-)
What are the two types of Electric Fields?
Point Charge Fields- equial to "real" gravity or gravity in space

Constant electric fields- equate to "assumbed" gravity or gravity near earth
What is the equation for the force of a constant E-field
To derive the correct electric field equation, simply apply what you already know for gravity

For gravity near earth: F=mg
therefore
For a constant E-field: F = qE

Where q= the charge and E= strength of electric field
to learn all of the electric field equations, it is best to know how they relate to each other

knowing the gravitation equations, what is the corresponding electric field equation conversion for:
g (streingth of gravitational field)
g (streingth of gravitational field) = E (strength of electric field)
to learn all of the electric field equations, it is best to know how they relate to each other

knowing the gravitation equations, what is the corresponding electric field equation conversion for:

G (constant)
G (constant) = K (constant)
to learn all of the electric field equations, it is best to know how they relate to each other

knowing the gravitation equations, what is the corresponding electric field equation conversion for:

h (distance)
h (distance) = r (distance)
to learn all of the electric field equations, it is best to know how they relate to each other

knowing the gravitation equations, what is the corresponding electric field equation conversion for:

m (inertial component)
m (inertial component) = q (charge, also an inertial component)
to learn all of the electric field equations, it is best to know how they relate to each other

knowing the gravitation equations, what is the corresponding electric field equation conversion for:

gh (gravitational potential)
gh (gravitational potential) = V (voltage)
What is the equation for the force of a point charge E-field?
To derive the correct electric field equation, simply apply what you already know for gravity

For real gravity: F=Gmm/r²
therefore
For a constant E-field: F = Kqq/r²
What is an equation that gives the strength a constant E-field?
To derive the correct electric field equation, simply apply what you already know for gravity

For gravity near earth: g=F/m (from F=mg)
therefore
For constant E-field: E=F/q (or E=V/d)
What is an equation that gives the strength a pint charge E-field?
To derive the correct electric field equation, simply apply what you already know for gravity

For real gravity: g=Gm/r²
therefore
For point charge E-field: E=Kq/r²
What is an equation for the electrical potential energy for a constant E-field?
To derive the correct electric field equation, simply apply what you already know for gravity

For gravity near earth: PE = mgh
therefore
For constant E-field: PE =qEd
What is an equation for the electrical potential energy for a point charge E-field?
To derive the correct electric field equation, simply apply what you already know for gravity

For real gravity: PE = -Gmm/r
therefore
For a point charge E-field: PE = -kqq/r or kqq/r
What is an equation for voltage for a constant E-field?
Ed
What is an equation for voltage for a point charge E-field?
V=Kq/r
how can voltage relate to potential energy?
V=PE/q

therefore

PE=Vq
A comparison is often made between the gravitational field near the earth and an electric field. It can be said that a rock near the earth has a "gravitational potential" similar to the difference in voltage that exists across a constant electric field. In this analogy, the "voltage" of the rock will:

A) increase if the rock is raised to a greater height above the ground
B) decrease if the rock is raised to a greater height above the ground
C) remain constant if the rock is raised to a greater height above the ground
D) increase if the rock is lowered to a lesser height above the ground
The strength of the electric field in a point-charge field changes with distance. However, in a constant electric field the field strength is constant. The formula for voltage in a constant field is V=Ed. In term of gravity, we could translate this to V=gh. As the rock moves upward, g does not change, but h does, increasing the "voltage" of the rock. Answer A is therefore correct.
what is a formula that conceptualizes resistance in circuits, heat flow and fluids?
R=pL/A

where, p=resistivity, L= length, A=cross-sectional area
What do capacitors do?
Store energy and charge by holding electrons on plates separated by a very small distance
What is the equation that relates capacitance to voltage and Q (the ratio of charges on the two plates)
C=Q/V
What is an equation for the PE stored by a capacitor?
1/2CV²
What is a Dielectric?
The dielectric is the substance between the two plates. All capacitors have a dielectric, even if it is just air. Other dielectrics are often inserted between the plates, such as gels and other composites. Once inserted, some energy stored in the capacitor is used to align the polar molecules in the dielectric instead of the capacitor, leaving a little more "room" for energy on the capacitor. Increasing dielectric strength, therefore, increasing capacitance
How should I conceptualize Capacitors?
Think of a capacitor as a large water tank that fills and empties via a spigot

Think of the dielectric as a separate container that is scooped into the tank and set aside. Later, as the tank drains, this water can be added back into the tank.
How does increasing or decreasing the surface area and distance between the plates of a capacitor effect capacitance?
In a parallel plate capacitor, capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the separation distance between the plates.
What are batteries?
Anything that separates charge creates voltage (i.e., potential difference created by differences in electron density) and can thus be thought of as a type of battery and will follow the same rules that apply to traditional batteries.
Does voltage change across a resistor?

How does current change across a resistor?
Yes, voltage always drops across any resistor

Current flow thru multiple resistors is always apportioned inversely with resistance. If one resistor has twice the resistance, it will receive half the current
How should I go about solving circuits?
FIRST: Simply the circuit by adding the components

A "simplified" circuit means no more than one of each component

SECOND: If you cannot get a simple circuit, use Krichoff's rules

THIRD: use V = IR (Ohm's Law)
You can only use Ohm's Law on a simplified circuit or across a single resistor (i.e., voltage drop across that resistor = I thru that resistor x R of that resistor
How do you add resistors?
Resistors in series: add directly

Resistors in Parallel: add the inverses and take the inverse
1/Rtotal=1/R₂+1/R₂
How do you add capacitors?
Capacitors in series: add the inverse and take the inverse
1/Ctotal=1/C₂+1/C₂

Capacitors in Parellel: add directly
How do you add batteries?
Batteries in series: add directly

Batteries in parallel: total voltage = the highest voltage of any one of the batteries in parallel
What is Ohm's Law?
V = IR

You can only use Ohm's Law on a simplified circuit or across a single resistor (i.e., voltage drop across that resistor = I thru that resistor x R of that resistor
What is Kirchoff's Rules
1st- Curent into a node = current out of a node

2nd- in any cyclical circuit, V=0 (i.e., the sum of the voltage drops across each resistor equals the total voltage of the battery)
What is the formulas for electrical power?

(only memorize one but derive the other 2 from Ohm's Law)
P=IV

use Ohms law (V=IR) to derive:
P=I²R ; P=V²/R
How do you create a magnetic field?
How do you create an electric field?

Give some common examples of things that create magnetic fields
Changing electric fields create magnetic fields and changing magnetic fields create electric fields

All of the following are involve moving charges and thus creates a magnetic field:
Nuclei (because the spin)
Electrons (because they orbit and spin)
Current
How do bar magnets work?
Normally, the electrons in a metal are approximately split between spin states, and thus the tiny magnetic fields they create cancel each other out. In a bar magnet they are all aligned, creating a net field
Which way do magnetic field lines run?
From north to south

Positive is north
Negative is south
What is the formula for the magnetic force on a moving charge particle in a magnet field?
F=qvBsin(theta)

Units = Ns/Cm or Kg/As²
Will the north pole of a magnet attract or repel positively charged particles?
Repel
What will be the affect of each of the following on the force experienced by a charged particle in a magnetic field?

a) velocity slows to vero
b) the particle moves at a angle of 90 degrees with respect to the field
c) at an angle of 180° with respect to the field
d) in the same direction as the field
a) No force
b) Maximum force given velocity and charge
c) No force
d) No Force
Right Hand Rule
pointing the thumb in the direction of the moving positive charge or positive current and the fingers in the direction of the magnetic field the resulting force on the charge points outwards from the palm. The force on a negatively charged particle is in the opposite direction
What would be the direction of the magneticfield vector for a current-carrying wire running from right to left across this page?
With right hand, point thumb in direction of current and curled fingers will indicate direction of B field
What would be the direction of the magnetic force vector for a charged particle moving at velocity v straight out of this page thru a magnetic field oriented from left to right across this page?
Force will be up the page if the particle is positively charged

and down the page if it is negatively charge
A bar magnet is placed near a pile of metal shavings. The shavings accelerate toward the magnet until they collide with and attach to its surface. The magnitude of the acceleration of the shavings toward the magnet could be decreased by which of the following:

A) impeding electron flow within the magnet
B)decreasing resistance within the magnet
C)increasing the distance between the magnet and the shavings
D) decreasing the mass of individual metal shavings
Changing electric fields are created with electrons move within a bar magnet. Changing electric fields always creates magnetic fields. The greater the change in the electric field, the greater the magnitude of the magnetic field created. Thus, impeding the flow of electrons would indeed decrease the magnetic force created by the magnet and subsequently decrease the acceleration of the shavings toward the magnet.

Answer A is therefore correct
A simple barometer is filled with mercury and allowed to equilibrate at atmospheric pressure. The mercury inside the barometer at equilibrium is 50 cm above the surface of the mercury at its base. What is the approximate atmospheric pressure? (S.G. mercury = 14)

A) 780 mmHg
B) 50 mmHg
C 70,000 Pascals
D. 7x10⁶ Pascals
pgh = (14 x 1000) x 10 x .5 = 70,000

C; Using a barometer, atmospheric pressure can be calculated by simply measuring the height of an evacuated cylinder that has been allowed to equilibrate at atmospheric pressure and then calculating the fluid pressure at the base of that column using P = pgh. This pressure will be equal to the atmospheric pressure. Plug the info given into pgh, remembering to change cm into meters and recalling that the density of water is 1,000 kg/m3 and thus mercury is 14 times that number. Your answer, whenever using pgh, or related equations, will be in Pascals
A large plastic barge is floating on a lake. A 5,000 kg crate of cinder blocks is placed on the barge for transport and the barge becomes 1/4 submerged in the water. Assuming the mass of the barge is negligible, what is the volume of the barge?

A) 500 m³
B) 200 m³
C) 20 m³
D) 50 m³
C
Many students have commented that they think this is a hard question. Yes, there are definitely questions of this difficulty level on the MCAT. The key to mastering these types of questions is to take it slowly and remember those key relationships regarding flotation, Archimedes' principle and the buoyant force. Run thru those in your head over and over until you see a connection. In this case, we know that the crate weighs 5,000kg. The most important thing to think of next is that since ¼ of the barge is submerged, enough water to fill ¼ of the barge also weighs exactly 5,000kg. This is because of the principle that any floating object displaces an amount of water exactly equal to its own weight (master this if you haven't already). We are asked for the volume of the barge. We know something about an amount of water that would fill ¼ of the barge, if we could figure out what volume that amount of water would fill, we could then just multiply by 4 to get the total volume of the barge. If we recall the density of water as 1,000 kg/m3, D=m/v solved for v will do just that. Plug and chug and you should find that the volume of water filled by 5,000kg of water is exactly 5m3. Since this is only the volume of ¼ of the barge, the total volume of the barge must be 4 times that, or 20m3
A certain block of unknown material floating on a lake has a density of 850 kg/m³. If the mass of the block is 2.5 x 10⁴ kg, what fraction of the block is floating above the water?

A. 0.5
B. 0.85
C. 0.35
D. 0.15
3) D; The principle tested here is that an object some fraction as dense as water will be that exact fraction submerged in water. This object is 850 kg/m3, which is .85 as dense as water. The mass is irrelevant information. It will float with .85 submerged. HOWEVER, note that the question asks for the fraction floating above the water, which would be the remaining .15 of the block.
A certain pipe of radius r has a volume flow rate of 100 m³/s. If the radius is tripled, which of the following gives the new flow rate?

A) 200 m³/s
B) 33.3 m³/s
C) 300 m³/s
D) 900 m³/s
D; The formula for volume flow rate is Q = AV. Be careful though, you cannot just equate an increase in radius directly with an increase in cross-sectional area. Even if you didn't know that, this is the kind of question you should ask yourself and then test to see if it's true: "let's see, how do you calculate area?" You get it from A = r2 and that can easily be substituted into the original equation to get Q = πr2V. Now we see from manipulating equations that tripling the radius will actually make the flow rate go up by a factor of nine.
Two balls of differing densities are both floating in an unknown liquid. Ball A has a specific gravity of 2.5 and Ball B ha a specific gravity of 2.0. Ball A is 1/4 submerged in the liquid, what fraction of Ball B is submerged?

A. 1/8
B. 1/5
C. 1/10
D. 1/6
B; Whenever you are given the fraction of one object that floats and asked for the fraction of another object that will float, you should first try to determine the density of the liquid. In this case, the ball is ¼ submerged and the SG of that object is 2.5. This means the liquid must be exactly 4 times as dense as the object, with as an SG of 10. Now we know from our basic principles that if the SG of the second ball is 2.0, it will be 1/5 submerged because it is 1/5 as dense as the liquid.
A given metal allow can withstand a pressure equal to 20 times normal atmospheric pressure. If the specific gravity of the alloy is 4.0, what is the maximum height of a cylindrical alloy column that will not be crushed under its own weight?

A. 5.0x10⁻⁴ m
B. 50 m
C. 12,000 m
D. 80 m
B; The concept of fluid pressure also works for solids and can be used to determine the pressure created at the base of a column of concrete, metal or other material. From the question we see that the alloy can withstand no more than 20 times atmospheric pressure. Atmospheric pressure in Pascals is 1 x 105, so 20 x 105 will be the max pressure. Set this number equal to pgh and solve for h. You should get exactly 50 meters.
A 20 coulomb charged particle is dropped into a parallel plate capacitor with very distant plates and experiences a force of 250 N. The distance between the plates is 2.0 meters. What is the voltage across the capacitor?

A. 12.5 V
B. 25 V
C. 5 V
D. 125 V
B ; To answer this question you must remember that the strength of a field is defined by the force it can exert on a given charge, expressed in N/C or in V/m (Why? Remember that V = Ed, solve for E). Calculate E using N/C and set that number equal to V/m, then solve for V
A 20 C positive charge is held a distance x away from a stationary 10 C negative charge. The positive charge is released and accelerates toward the negative charge, reaching a maximum velocity of 50 m/s as it collides with 10 C charge. How fa apart were the two particles? (Both particles have a mass of 2g; k=9x10⁹ Nm²/C²

A. 7.5 x 10¹¹ m
B. 2.5 m
C. 1.5 x 10⁸ m
250 m
A ; To solve this problem, recognize that there is a potential energy stored when these two particles are held apart, given by U = Kqq/r; When the particle is released, this energy is transferred into energy of motion, given by E = 1/2mv2. Set these two equal and solve for r (be careful with units!)
A positive charge is held at point A, close to another fixed positive charge and then released. The charge is allowed to accelerate for a few moments and then stopped at point B. Which of the following best describes the change in voltage?

A. Voltage increases from point A to point B
B. Voltage decreases from point A to point B
C. Voltage is at a maximum when the particles are an infinite distance apart
D. Voltage remains constant
B ; Voltage is potential energy per unit charge. Since the charge doesn't change from point A to point B, the increase or decrease in voltage depends on potential energy. Two particles that repel each other have the most potential energy when they are closest together, so going from point A to point B voltage decreases.
A hand-held calculater uses two small electrodes separated by a small distance of 2cm, with a potential difference of 10V. The current across the electrodes is 1.0x10⁻⁴ A.

What is the strength of the electric field between the two electrodes?

A. 500 N/C
B. 5 N/C
C. 50 V/m
D. 200 V/m
A ; To answer this question correctly, you must remember that V/m and N/C are equivalent units for electric field strength, E. Simply take the voltage from the problem, divide it by the meters (note you must change cm to meters) and you have the field strength. The correct answer could be given in either N/C or V/m.
Two small parallel plate capacitors have identical properties and are connected to one another by a conducting wire. Both capacitors are connected to a cyclical circuit containing a battery and a resistor. Of the voltage across each capacitor is 20 V and the capacitance of each is 10 C/V, what is the total potential energy stored in the two-capacitor system?

A. 1 KJ
B. 2 KJ
C. 4 KJ
D. 0 KJ
C ; The question asks for the potential energy stored on the two capacitors, which should immediately make you think of the equation for PE of a capacitor: U = 1/2QV. I also told you that if you don't have all the variables (Q in this case), plug in some derivation of C = Q/V; this gives the formula U = 1/2CV2. Using our rules for adding capacitors (these are in series) you get a total capacitance of 5 C/V. HOWEVER, since you have added the two together and you are also including voltage in your calculation, you must consider the total effective voltage as well. These two capacitors have a voltage across them, and anything with a potential across it follows the rules for adding batteries. These are in series so you add them, giving a total voltage of 40V. Plug these two into our equation above and you should get 4,000J or 4KJ.
A 10 kg block is submerged in water and has an apparent mass of only 5 kg. What is the density of the block?

A. 1.0 g/cm₃
B. 5.0 g/cm₃
C. 2.0 g/cm₃
D. 1.5 g/cm₃
C; To answer these apparent weight/apparent mass questions you must be 100% conceptually sound on Archimedes' principle and buoyancy. The most important thing to remember is that the BUOYANT FORCE is exactly equal to an objects apparent weight loss in Newtons. If the weight loss is given in grams or Kg, then we can say that the weight loss in g/Kg is EXACTLY the mass of that much volume of the fluid. In this case, the block had a mass of 10kg out of water and 5kg in water. This means a "blocks-worth" of whatever the block is made of is two times as massive as a blocks-worth of the fluid. You should know the density of water to be 1.0g/cm3. Multiply this by two to get 2.0g/cm3, or Answer C.
A 25 k lead ball is placed in an unknown liquid and suffers an apparent weight loss of 25 N. What is the specific gravity of the unknown liquid? (density of lead= 11.3 g/cm³)

A. 5.65
B. 11.3
C. 1.13
D. 2.21
C; Very similar to the previous question, but asked in a different way. Here, you simply change the mass of the ball, 25kg to Newtons, 250N. The ball suffers an apparent weight loss of 25 N. Again, this tells us that a balls-worth of the fluid weighs only 25N while a balls-worth of lead weighs 250N. The fluid is thus 10 times LESS dense than lead, or 1.13g/cm3 with a specific gravity of 1.13.
Assuming a constant temperature, which of the following will increase the resistance in a current carrying wire?

I. Increasing the length of the wire
II. Decreasing the diameter of the wire
III. Increasing the voltage across the wire
IV. Increasing current

A. I only
B. I and II
C. I, II and III
D. I, II and IV
B; To answer this question, recall that resistance is a characteristic of the material, NOT something that varies with voltage, current, or the other aspects of the circuit. Resistance is only affected by temperature, or by the dimensions of the conduit according to R = pL/A, where p is resistivity, a measure of the natural resistance of the material, L is the length of the wire and A is the cross-sectional area of the wire. This makes Statements I and II true. Statements III and IV are not true and are not found in the above equation. Note that in V = IR voltage and current are the two variable entities. Resistance is set, unless you take out a resistor and put in another one with a different resistance.
If a switch is closed ans a small amount of current is allowed to pass thru a wire for one second, the very first electron thru the switch will be found where after the switch is closed?

A. in the valence of the last atom in the wire
B. in the valence of the first atom in the wire
C. moving continuously from one atom to another
D. the electron could be associated with any atom within the wire
B; The MCAT frequently tests your understanding of how current actually passes thru a wire. The first electron to enter the wire will displace an electron in the valence shell of the first atom it encounters. The electron displaced will then displace an electron in a neighboring atom, and so on. Thus, the first electron will be associated with the very first atom it encounters unless or until it is displaced by another electron passing thru the wire. This makes B the best answer.
For a simple circuit containing a battery, a resistor and a capacitor, which of the following changes will increase the strength of the electric field between the capacitor plates?

A. increasing the resistance
B. decreasing the resistance
C. decreasing the distance between the capacitor plates
D. increasing the current within the circuit
C; The constant electric field that exists between the plates of a capacitor is a function of voltage and distance. This can be seen by rearranging the equation V = Ed to get E = V/d. Increasing voltage will increase E as will decreasing d. Changing resistance or current will not change the E field as long as voltage and distance remain unchanged.
As a fully charged capacitor is discharged, which of the following describes the movement of the electrons thru the space between the plates?

A. Electrons move at a constant speed
B. Electrons experience a constant acceleration
C. Electrons experience anon-constant acceleration
D. Electrons lose speed at a constant rate as they approach the second plate
B; When an electron leaves the first plate it has a potential energy that is changed into kinetic energy as the electron flies toward the positively charged plate. Because there is a constant force on the electron due to the electric field, according to F = ma, there must be a constant acceleration. This makes B the only possible answer.
Which of the following formulas can be used to approximate the maximum kinetic energy of an ejected electron as it collides with the positive electrode? (assume hf just esceeds the work function; r= the distance between the electrodes)

A. Kqq/r₂
B. qEr
C. Kqq/r
D. mgh
B; If the energy of the photon barely exceeds the work function, the final kinetic energy of the photon depends entirely on the electrical potential energy of the electron the moment it is ejected. This is given by PE = qEd (or in this case qEr). Answers A and C are incorrect because they apply to point charge fields, not constant electric fields. Answer D is false because mgh gives gravitational potential energy which is not involved in increasing electron velocity between the electrodes.
Gravity
gravity is a field that exists between any two objects of mass
Think of a field as an invisible influence that can exert a force on a mass or charge
Universal Law of Gravitation
F=(Gmm/r^2)
G=6.67E-11 M^3/kg*s^2
This equation is true everywhere, however, on earth we simplify it to be F=mg
Gravitational Potential Energy
PE=mgh (near earth)
PE= (-Gmm/r) (in space)
Friction
Friction opposes sliding, not motion
Kinetic Friction v. Static Friction
If there is sliding, its kinetic friction; if there is no sliding, its static friction
Force of Friction
F=µFn
F=µ(mg)cos(ø)
Inclined Planes
F=mgsinø (Force down an inclined plane, parallel to the surface)
Fn=mgcosø (Normal Force of an inclined plane)
Vf=sqrt(2gh) (velocity at the base of an inclined plane)
Hooke's Law
F=k∆x (where x is the displacement of the spring from its equilibrium point, NOT the length of the spring)
Elastic Potential Energy
PE=1/2k∆x^2; this is the potential energy stored in a compressed spring or any other object that follows hooke's law
Pendulum
any weight attacghed by a rod, string, wire, etc. to a fixed overhead point and capable of freely swinging from side to side
PE is highest at max height of the bob
KE is highest at the bottom of the arc
Simple Harmonic Motion
Anything that oscillates back and forth and can be represented by a sine wave graphically constitutes simple harmonic Motion
Simple Harmonic Motion Formulas
T=2π*√(m/k) [mass on a spring]
T=2π√(L/g) [pendulum]
SHM Questions to consider
What will be the effect of changing the following aspects of a mass-spring system?
mass on the spring, length of the spring, mass of the spring, gravity, the spring constant

What will be the effect of changing the following aspects of a pendulum?
mass of the pendulum bob, length of the pendulum, gravity
Static V Dynamic Equilibrium
Objects at rest are in static equilibrium; objects moving at a constant velocity are in dynamic equilibrium. In both cases the net force experienced by the object must be zero
Examples of equilibrium
Terminal velocity, Constant velocity, objects at rest, balanced fulcrums or boards hanging from strings, objects floating in a liquid
Formulas for Torque
T=Fl
T=mgl
T=Frsinø (where l=lever arm and r= distance between the force and the point of rotation; rsinø always = l, but r=l only when ø = 90º)
Circular Motion
Fc=mv^2/r
Centripetal Force
It is always caused by some other force. (friction, gravity, tension). Centripetal Force is really just a categorical name for all forces that act to pull things into circular motion
Centrifugal Force
forms an action reaction pair with centgripetal force. For example, if a string is pulling a ball into circular motio, the ball must also be pulling on the string. The string's force on the ball is centriptal and the ball"s force on the string is centrifugal. the centrifugal force would be equal and opposite, in a direction away from the center of the circle.
Angular Motion Formulas
w=v/r, C=2πr
w= 2πf, C=πd
w= angular frequency in rad/s
v= tangential velocity in m/s
r= radius
Facts to know about Angular Motion
One rotation of a circle is equal to 6 radians
2π rad/360º or πrad/180º
Momentum
p=mv
Momentum= inertia increase by velocity
Momentum is ALWAYS conserved in an isolated system
Conserved
Conserved means remains constant or is the smae before and after. You will see this applied most frequently to collisions. For any collisio in an isolated system momentum will always be conserved. in this case, isolated means that there are no net external forces acting on the system. Friction, drag and applied forces are common examples of external forces.
Impulse
Impulse=∆p
Impulse=m∆v
Impulse= (Favg)*t
If there is no change in velocity then there can be no impulse
The greater the change in velocity the greater the impulse
Elastic Collisions v. Inelastic Collisions
In an elastic collision momentum and energy are both conserved. In an inelastic collision, momentum is conserved but energy is not
Elastic Collisions
(1/2mv^2)a+(1/2mv^2)b=(1/2mv^2)a+(1/2mv^2)b
(KE of object one before + KE of object two before= KE of object one + KE of object 2 after)
Conservation of Relative Velocity
For completely elastic collisions only, the relative velocity before will equal the relative velocity after. Why?
Objects Exchange Velocities
If the objects are of equal mass and the collision is perfectly elastic, the two objects will exchange velocities before and after the collision. Why?
Inelastic Collisions
m1v1+m2v2=m1v1+m2v2
Always use conservation of momentum
YOU MUST USE SIGNS. Any velocity vector to the left or down must be given a negative sign
Perfectly Inelastic collisions
m1v1+m2v2=(m1+m2)v3
Reverse Collision
Provide at least three examples of reverse collisions:
Radioactive Decay, Skydivers separating, shotgun pellets
Solids
Stress=force/area
Strain= ∆dimension/original dimension
Moduli of Elasticity
(ME)= stress/ strain [general formula]
Thermal Expansion
∆L= alpha L ∆T
When solids are heated, they expand. When they are cooled, they shrink. WAter is weird
Energy Forms
KE, PE Gravitational, PE Elastic, PE Electrical, PE Capacitor, Internal Energy, Heat energy, Chemical energy, Mechanical energy
Mechanical Energy
ME=KE+PE
In the absence of non-conservative forces such as friction, drag, air resistance, etc. , mechanical energy is always conserved (AKA total energy)
Law of Conservation of Energy
Energy in an isolated system is always conserved. If the system is not isolated, energy will not necessarily be conserved
(Provide a conceptual definition for each of the following kinds of systems: Open, closed and isolated)
Work Formulas
Think of work in exactly this way and in this exact order:
W=∆Energy
w=Fdcosø
Use the formulas above to determine the units that make up a joule. When is work positive, when is it negative?
First law of thermodynamics
∆E=W+q
Work is energy transfer via a force
Head is energy transfer via friction or energy flow from hot to cold
The Work-Energy Theorem
If all motion is in the horizontal plane, and no other forms of energy are involved, the work done is simply the change in kinetic energy of the object
W=KEf-KEi
Machines
Machines never reduce or change the amount of work. They Reduce the amount of force necessary to perform a given amount of work
Ramps
F=mg(h/d)
Levers
F=mg(L1/L2)
where L1 and L2 refer to the lever arms for the mass and the applied force respectively
Pulleys
F=mg/(# of vertical ropes directly lifting the mass)
Hydraulic Lifts
F=mg(h1/h2) or F=mg(A1/A2) where h1 and h2 refer to the distance traveled by the large plunger and the small plunger, respectively; and A1 and A2 refer to the cross sectional areas of the small plunger and the large plunger respectively
Power
Think of power in EXACTLY this way and in this EXACT order:
P=∆E/t
P=W/t
P=Fdcosø/t
P=Fvcosø
Adenine
a base found in DNA and RNA and derived from purine, Nitrogen base that pairs with thymine via 2 H-bonds
Thymine
a base found in DNA (but not in RNA) and derived from pyrimidine, pairs with Adenine via 2 H-bonds
Cytosine
a base found in DNA and RNA and derived from pyrimidine, Nitrogen base that pairs with guanine via 3 H-bonds
Guanine
a purine base found in DNA and RNA, The base that pairs with Cytosine in via 3 H-bonds
Which DNA nucleotides are purines?
A and G
Which DNA nucleotides are pyrimidines?
C and T and U (Uracil)
Bidirectional
characteristic of DNA replication meaning it proceeds in both directions from the origin
Semi-conservative
method of replication that implies that each new strand of DNA is half original and half new
Semi-discontinuous
DNA replication half done all continously (leading strand) half done discontinously (lagging strand)
Differences Between DNA and RNA
DNA stays in the nucleus, RNA is single stranded has a 2' hydroxyl group. RNA contains Uracil, not Thymine. RNA has three forms (mRNA, tRNA, rRNA). RNA exits the nucleus into the cytoplasm.
Telomere
The protective structure at each end of a eukaryotic chromosome. Specifically, the tandemly repetitive DNA at the end of the chromosome's DNA molecule. See also repetitive DNA.
Telomerase
an enzyme in eukaryotic cells that can add telomeres to the ends of chromosomes after they divide
RNA polymerase
an enzyme that starts the formation of RNA by using a strand of DNA molecule as a template
Promoter
A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA.
mRNA
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein; also called messenger RNA.
tRNA
type of RNA molecule that transfers amino acids to ribosomes during protein synthesis
rRNA
The most abundant type of RNA, which together with proteins froms the structure of ribosomes. Ribosomes coordinate the sequential coupling of tRNA molecules to mRNA codons; also called ribosomal RNA.
Exon
sequence of a gene's DNA that transcribes into protein structures
Intron
sequence of a eukaryotic gene's DNA that is not translated into a protein
pre-mRNA
a form of messenger RNA that contains both introns and exons
Lac Operon
The operon that controls the metabolism of lactose
Lactase
any of a group of enzymes (trade name Lactaid) that hydrolyze lactose to glucose and galactose
Gene Regulation Mechanisms
1. Rate of transcription- DNA gets transcribed continuously because of RNA's short half-life
2. Activators and repressors- upregulation and downregulation of DNA transcription (i.e. lac operon)
3. Permanent or Semi-permanent repression- methylation or other covalent modification that prevents transcription.
Genetic Code
sequence of nucleotides that specifies the amino acid sequence of a protein
Start Codon
AUG; the codon that begins all RNA.
Stop Codon
UAG, UAA, or UGA; the codon that ends all RNA.
elongation
addition of amino acids to the polypeptide chain; continues until it reaches a stop codon
termination
stop of mRNA synthesis (i.e., transcription) at the terminator site
Translation
(genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm
Germ Cell
A cell that undergoes meiosis cell division and produces gametes
Somatic Cell
any of the cells of a plant or animal except the reproductive cells
Mutation
change in a DNA sequence
Point Mutation
mutation that affects a single nucleotide, usually by substituting one nucleotide for another
Missense Mutation
a base-pair substitution that results in a codon that codes for a different amino acid
Neutral Mutation
a mutation that has little or no effect on the function of the encoded protein
Silent Mutation
A mutation that changes a single nucleotide, but does not change the amino acid created.
Frameshift Mutation
mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide
Nonsense Mutation
a mutation that changes an amino acid codon to one of the 3 stop codons, resulting in a shorter and usually nonfunctional protein
Non-disjunction
meiosis in which there is a failure of paired homologous chromosomes to separate
Chromosome Deletion
Fragment is lost after chromosome broken
Malignant Cancer
cancer causing tumor, cells travel and infect other areas of the body
Benign Cancer
does not invade surrounding tissue or spread to other parts of the body.
Metastasis
The spread of cancer cells to locations distant from their original site.
proto-oncogenes
normal cellular genes that are important regulators of normal cellular processes, they promote growth. alterations in the expression of these cells resulr in oncogenes
oncogenes
Genes that cause cancer by blocking the normal controls on cell reproduction.
Carcinogens
Substances and agents that are known to cause cancer
P1 Generation
parental generation
F1 Generation
offspring of the P generation
F2 Generation
offspring of the F1 generation
test-cross
the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype
true-breeding
describes organisms or genotypes that are homozygous for a specific trait and thus always produce offspring that have the same phenotype for that trait
self-pollinate
happens when pollen is transferred from the male to the female reproductive structure in the same plant
Mendelian Ratio
The characteristic dominant-to-recessive phenotypic ratios that Mendel observed in his genetics experiments. For example, the F2 generation in a monohybrid cross shows a ratio of 3:1; the F2 generation in a dihybrid cross shows a ratio of 9:3:3:1.
phenotype
physical characteristics of an organism
genotype
genetic makeup of an organism
heterozygous
having two different alleles for a trait
homozygous
having two identical alleles for a trait
gene
A segment of DNA on a chromosome that codes for a specific trait
allele
an alternative form of a gene
locus
the specific site of a particular gene on its chromosome
Law of Segregation
first law of heredity stating that pairs of alleles for a trait separate when gametes are formed
Law of Independent Assortment
the law that states that genes separate independently of one another in meiosis
Hemophilia
Sex linked disorder (on X chromosome); inability to clot blood
incomplete dominance
creates a blended phenotype; one allele is not completely dominant over the other
co-dominance
situation in which both alleles of a gene contribute to the phenotype of the organism
incomplete penetrance
Not all individuals with a mutant genotype show the mutant phenotype
polygenic
of or relating to an inheritable characteristic that is controlled by several genes at once
pleiotropy
the control of more than one phenotypic characteristic by a single gene
mosaicism
the condition in which an organism has two or more cell populations that differ in genetic makeup
genetic imprinting
different expression of a gene depending on if its inherited from mom or dad
poly-A-tail
A string of several hundred adenine nucletodies added to the 3' end of the eukaryotic mRNA.
5' cap
The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide.
Inversion
(genetics) a kind of mutation in which the order of the genes in a section of a chromosome is reversed
gene pool
consists of all genes, including all the different alleles, that are present in a population
evolution
a process in which something passes by degrees to a different stage (especially a more advanced or mature stage)
polymorphisms
naturally occurring variations in the structures of genes and the products they make for the body
niche
full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions
survival of the fittest
organisms that are most adapted to their environment survive
natural selection
a natural process resulting in the evolution of organisms best adapted to the environment
R-selection
have as many offspring as possible as fast as possible (fish, insects)
K-selection
The concept that in certain (K-selected) populations, life history is centered around producing relatively few offspring that have a good chance of survival.
divergent evolution
when two or more species sharing a common ancestor become more different over time
convergent evolution
when two or more species NOT descended from a common ancestor develop similar traits
A bat and a bird both have wings. Is this example convergent or divergent evolution?
convergent evolution
Hardy-Weinberg Equilibrium
theory of a stable, nonevolving population in which frequency of alleles do not change; only occurs in large, isolated populations with random mating, and no natural selection or mutations
Hardy-Weinberg assumptions
1. Large population
2. No mutation
3.No immigration or emigration
4.Random mating
5. No natural selection
H-W equations
p² + 2pq + q² = 1
p + q = 1
p² + 2pq + q² = 1
What do the terms p², 2pq, q² represent?
p² is the predicted frequency of homozygous dominant (AA) people in a population, 2pq is the predicted frequency of heterozygous (Aa) people, and q² is the predicted frequency of homozygous recessive (aa) ones
p + q = 1
What does p and q represent?
p equals all of the alleles in individuals who are homozygous dominant (AA) and half of the alleles in people who are heterozygous (Aa) for this trait in a population
If 90 out of every 1000 individuals in a population have a recessive phenotype, which of the above terms are know or can be calculated?
all
What are the different taxonomic classification levels?
Kingdom, Phylum, Class, Order, Family, Genus, Species
Name of each group that humans belong to?
KINGDOM - Animalia
PHYLUM - Chordata
CLASS - Mammalia
ORDER - Primates
FAMILY - Hominidae
GENUS - Homo
SPECIES - Homo sapiens
What is the general criteria scientists use to decide how to classify organisms?
-Individuals in the same group must be more similar to each other than they are to members of different groups
-Evidence of an ancestral state = less argument for separate classification
-Evidence of a degenerative state = more argument for separate classification
-Members of different species should not be able to mate with one another and produce normal, viable, fertile offspring
mutualism
a relationship between two species in which both species benefit
commensalism
a relationship between two organisms in which one organism benefits and the other is unaffected
parasitism
relationship in which one partner obtains nutrients at the expense of the host
latent period (virology)
the time that elapses before the presence of a disease is manifested by symptoms
virulence
degree of pathogenicity (ability to produce disease)
temperateness (virology)
the ability of some bacteriophages to display a lysogenic life cycle or integration of the bacteriophage nucleic acid into the host bacterium's genome
dormant virus
a virus that is incorporated into the genome of its host and is not active
provirus
viral DNA that has attached to a host cell's chromosome and that is replicated with the chromosome's DNA
reverse transcriptase
enzyme carried in the capsid of a retrovirus that helps produce viral DNA from viral RNA
retrovirus
An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses.
virus
particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells
A man is found to be HIV positive. Is this an example of a virus in a lytic or a lysogenic cycle?
lysogenic cycle
vaccine
dose of a disabled or destroyed pathogen (or part of a pathogen) used to stimulate a long-term immune defense against the pathogen
Why do some vaccines tend to lose their effectiveness from year to year and require alteration?
Viruses mutate constantly producing new strains and markers.
Remember that all bacteria are _________.
prokaryotes
bacilli
rod-shaped bacteria
cocci
sphere-shaped bacteria
spirilla
spiral-shaped bacteria
Bacteria reproduce via ______ ______.
binary fission
conjugation
In bacteria, the direct transfer of DNA between two cells that are temporarily joined. One bacteria must have an F plasmid (F+); the F plasmid is a plasmid containing the gene for a sex pilus. The recipient can be (F-).
transformation
pick up DNA from environment
transduction
viruses accidentally incorporate host genetic material into their nucleic acids
What are the major differences between mitosis and binary fission?
binary fission- a prokaryotic cell divides into two by simple division of nucleus along with cell membrane there is no formation of spindle fibers (as in mitosis), and no equational division of chromosomes .
mitosis- four daughter cells are formed whereas in binary fission only two daughter cells are formed
gram positive
-stain purple
-very thick cell wall
-form endospores
-single cell membrane
gram negative
-stain pink
-relatively thin cell wall
-do NOT form endospores
-contain two cell membranes: one inside the cell wall and one outside the cell wall
Differences between prokaryotes and euthrocytes?
Prokaryotic cells:

-Most primitive, earliest form of life
-Do not have a pre-defined nucleus
-Chromosomes are dispersed in the cytoplasm
-Contain no membrane-bound organelles
-Have circular chromosomes and lack histone proteins
-Most metabolically diverse
-Small - typically 1 - 5 micrometers in diameter
-Have a primitive cytosketetal structures or don't have a cytoskeleton at all
-Smaller (70S) ribosomes
-Don't undergo meiosis but reproduce sexually by the transfer of DNA fragments through conjugation


Eukaryotic cells:

-More complex, evolved organsims
-Contain true nuclei in which chromosomes are compacted as chromatin
-Contain membrane-boundorganelles
-Have linear DNA and contain histone proteins
-Larger - typically 10-100 micrometers in diameter
-Have a complex cytosketeton
-Larger (80S) ribosomes
-Reproduce sexually with the use of meiosis
Why are nitrogen-fixing bacteria found in soil so important?
Nitrogen fixing bacteria change nitrogen into the form of soluble nitrates so that plants can use it.
Chemotroph
an organism that gets its energy from chemicals taken from the environment
Phototroph
an organism that gets its energy from sunlight
Autotroph
an organism that produces its own nutrients from inorganic substances or from the environment instead of consuming other organisms
Heterotroph
an organism that depends on complex organic substances for nutrition, must consume nutrients and cannot make it's own
How are fungi classified? ex. _______troph
heterotroph
All fungi are ________ meaning they obtain nutrients from consuming dead matter.
saprophytic
Fungi have cell _____ made of ______.
walls, chitin (a glucose polymer)
What is the growth phase of fungi called?
hyphae = haploid
Most fungi can reproduce both sexually and asexually? True or False
True
When do fungi reproduce sexually?
When life is hard (stress, little food, bad environment, etc.)
When do fungi reproduce asexually?
When life is good.
What is an alcohol?
Any species with an -OH functional group.
Can alcohols behave as a nucleophile or Lewis acid?
Both! As nucleophiles, the lone pair on oxygen acts as a Lewis base. As Lewis acids, the oxygen accepts a pair of elecrons from the O-H bonds as the proton is abstracted.
Do alcohols have a higher or lower boiling and melting point due to hydrogen bonding?
Higher.
Are alcohols soluble in water?
Yes, most alcohols are soluble in water. The hydroxyl functional group gives it a polar nature. This polarity of the compound helps it dissolve in polar water. Long alkyl chains reduce solubility.
True or False: Alcohols are more acidic than H2O.
False. Alcohols are LESS acidic than H2O. Water is a neutral substance. Alcohols can be both acidic and basic.
What are some common oxidizing agents of an alcohol?
O3, Cr2O7, CrO4, KMnO4.
NaBH4 can only reduce _____ and _____.
Aldehydes and ketones. This is because it is not as reactive as the stronger reducing agents.
LiAlH4 and H2/pressure can reduce what four functional groups?
Aldehydes, ketones, carboxylic acids, and esters.
Name the steps for dehydration of an alcohol. What does it form?
1. Alcohol is protonated by the acid.
2. The "good leaving group water" leaves, forming a carbocation.
3. Methyl or hydride shifts can occur, but only if it results in a more stable carbocation.
4. Water molecule abstracts a proton and the electrons collapse to quench the carbocation and form an alkene.
Grignard Synthesis
R-MgX + carbonyl becomes tertiary carbon with R group and oxygen ion, acid turns to alcohol. Results in an increase in the number of carbons.
What electrophilic double bonds will also work with the Grignard reaction?
C=N, cyano groups, S=O and N=O.
Name the steps for formation of an alkyl halide from an alcohol.
1. Alcohol acts as nucleophile, attacking the electrophilic halide hydrogen and forming the good leaving group water plus a halide ion.
2. The halide ion attacks the central carbon via SN2, kicking off water.
Name the steps for formation of tosylates/mesylates.
1. Alcohol attacks the tosyl or mesyl halide via SN2, kicking off the halide ion.
2. A hydrogen is abstracted by the halide ion, quenching the charge on the oxygen.
Pinacol rearrangement
- a dehydration of an alcohol that results in an unexpected product.
- when hot sulfuric acid is added to an alcohol, the expected product is an alkene.
- however, if the alcohol is a vicinal diol, the product will be a ketone or aldehyde.
What characteristics make ethers excellent solvents?
Ether is very non-reactive, weakly polar, soluble in water, most non-polar species are soluble in ethers, low boiling point (no H-bonding).
MCAT tip concerning ethers:
It will almost always be the solvent and NOT the ether participating in a reaction. If ethers do react, it will only be after the oxygen is protonated by strong acid. The resulting unstable intermediate could then be attacked by any good nucleophile.
Epoxides
- 3 membered cyclic ethers
- more reactive than typical ethers due to ring strain
- react with water in the presence of an acid to form diols.
- this is anti-addition.
Why do carbons almost never act as nucleophiles under standard conditions during Grignard Synthesis?
Carbon is far more electronegative than the metal (R-MX), allowing it to increase its electron density dramatically via induction. Metals have the ability to give up valence electrons easily.
Electron Flow
electrons flow from high concentration to low concentration during reactions
Bases
-Bases abstract (pull away) protons
-are electron dense and will not share their electrons
-proton acceptors
Nucleophiles
-attack carbon
-are electron dense but willing to share electrons
Electrophiles
-electron poor species with a full or partial positive charge
Common bases
Sodium Hydroxide - NaOH
Potassium Hydroxide - KOH
Ammonium Hydroxide - NH4OH
Calcium Hydroxide - Ca(OH)2
Magnesium Hydroxide - Mg(OH)2
Barium Hydroxide - Ba(OH)2
Aluminum Hydroxide - Al(OH)3
Ferrous Hydroxide or Iron (II) Hydroxide - Fe(OH)2
Ferric Hydroxide or Iron (III) Hydroxide - Fe(OH)3
Zinc Hydroxide - Zn(OH)2
Lithium Hydroxide - LiOH
Common nucleophiles
-X (any of the halides)
-NH₃
-CN
-OH
-SH
-OR
-SR
Common electrophiles
proton (H3O+)
alkyl halide (CH3-Br)
alcohol (CH3-OH)
aldehyde (CH3 - CHO)
ketone (CH3 - CO - CH3)
acid chloride (CH3 - CO - Cl)
ester (CH3 - CO - OCH3)
borane (BH3)
boron trifluoride (BF3)
thionyl chloride (Cl - SO - Cl)
phosphorous trichloride (PCl3)
E1 (elimination, unimolecular)
-Rate depends on the concentration of ONE species only and is thus FIRST ORDER
2 steps:
1) The dissociation of the leaving group, resulting in formation of a carbocation [slow step]
2) The single-step abstraction of a proton with collapse of the electrons to form a double bond (which quenches the carbocation) [fast step]
E2 (elimination, bimolecular)
-Rate depends on the concentration of TWO species only and is thus SECOND ORDER
1 step:
1) The single step abstraction of a proton with collapse of the electrons to form a double bond
SN1 (nucleophilic substitution, unimolecular)
-Rate depends on the concentration of ONE species only and is thus FIRST ORDER
2 steps:
1) The dissociation of the leaving group, resulting in formation of a carbocation [slow step]
2) Attack of the carbocation by the nucleophile [fast step]
SN2 (nucleophilic substitution, bimolecular)
-Rate depends on the concentration of TWO species only and is thus SECOND ORDER
1 step:
1) The single step "back-side attack" of the electrophile with simultaneous ejection of the leaving group
Alkanes
Compounds made entirely of carbon-carbon or carbon-hydrogen single bonds
Properties of alkanes
-Insoluble in water
-Very low density
-Nonpolar
-Most are oils or gases
Boiling point trends
-Increases with increasing chain length and molecular weight
-Branching significantly lowers boiling pt
Melting point trends
-Increases with increasing chain length and molecular weight
-Decreases with branching
primary carbon
one carbon neighbor
secondary carbon
two carbon neighbors
tertiary carbon
three carbon neighbors
quaternary carbon
four carbon neighbors
Cyclohexane
-most stable ring structure
-zero ring strain
-strain increases when you add more or less carbons
Axial substituents
rise vertically from the ring
Equatorial substituents
extend horizontally from the ring
more stable than axial
Combustion of alkane
a violent, radical, chain reaction with oxygen requiring a very high energy of activation
CH₄ + 2O₂ → CO₂ + 2H₂O + Heat
Radical Halogenation of an Alkane
Alkanes react with F, C, or Br (not iodine) in the presence of heat or light via a radical chain reaction
-The major product-forming step is propagation, NOT termination
Radical Stability
Tertiary > Secondary > Primary
Reactivity vs. Stability
-"Reactive" halogens will bond mostly to the least substituted carbon
-"Selective" halogens will bond mostly to the most substituted carbon
Reactive halogens (decreasing order)
F > Cl > Br
Selective halogens (decreasing order)
Br > Cl > Br
Synthesis of an Alkane from an Alkene
Alkene + H₂/Metal catalyst → Alkane
example of syn addition (same side)
Alkene
-any species with a double bond
-alkenes are nucleophiles
-are weakly electron withdrawing (when located one C away from another atom)
Alkene stability
alkyl substituents (R-groups) increase stability
tetrasubstituted > trisubstituted > disubstituted > monosubstituted > unsubstituted
Alkyne
any species with a triple bond
Benzene
a cyclohexane ring with alternating double and single bonds
3 representations:
Ar-, Ph-, and C₆H₅-
Phenyl
benzene attached directly to the primary chain
Benzyl
benzene attached to a CH₂ group, which is then attached to the primary chain
The polar layer will usually be the top or bottom layer in a separatory funnel?
bottom layer
Gravity VS. Vacuum filtration
Gravity filtration is used for when the desired product is in solution (usually hot) where as vacuum filtration has the desired product being a solid.
vacuum distillation...what is it?
A vacuum is used to reduce the atmosphere pressure to decrease the boiling point. This technique is used when the compounds have high boiling point.
What is the Rf value in paper chromatography?
Rf = distance traveled by component/total distance traveled by solvent.
What comes out first/travels the furthest in all types of chromatography, polar or non-polar components?
The least polar component will come out first.
Column Chromatography
where a solution containing the mixture is dripped down a column containing the solid phase (usually glass beads). the more polar compounds in the mixture travel more slowly down the column, creating separate layers for each compound. each compound can subsequently be collected as it elutes with the solvent and drips out of the bottom of the column
How many peaks will there be in a sample with 2 compounds in a gas chromatograph?
2 peaks. 1 for each compound.
Mass Spectrometry
The height of each peak gives the RELATIVE abundance of each individual fragment with a unique m/z. (Mass divided by charge...also called the mass to charge ratio)
IR Absobancy of C=O
1700, Sharp and Deep
IR Absorbancy of OH
3300, Broad separate from CH
IR absorbancy of Saturated Alkane CH
2800, Sharp, Deep
IR Absorbancy of Carboxylic Acid, OH
3000, Broad overlaps CH
IR Absorbancy of Amine NH
3300, Broad, shallow
IR Absorbancy of Amide NH
3300 Broad, Deep
IR Absorbancy of Nitriles CN
2250 Sharp, Deep
IR frequency is determined by ______ , _______ and _________.
1) The length of the bond 2) strength of the bond 3) molecular weight of the two atoms involved in the bond.
What do atoms have to have to be read by an NMR machine?
Odd atomic number or odd atomic mass
IR won't read a bond with _________
no dipole
What do the peaks represent in a NMR spectra?
They represent the all of the hydrogens in a molecule that share an indistinguishable chemical environment. These are called equivalent hydrogens.
NMR--- What causes Splitting?
The presence of "neighbors" (non-equivalent hydrogens attached to a neighboring carbon) causes splitting of the peak. The peak for a set of equivalent hydrogens will be split into n +1 sub-peaks.
What does the area under the peak in a NMR spectra represent?
Relative number of hydrogens accounted for by that peak.
How to bonds show up on a UV spectra?
Molecule with only single bonds show little or no UV absorbtion. Double and triple bonds absorb the UV strongly. Conjugated systems absorb UV even more strongly than isolated double or triple bonds.
UV spectra graphs _______ vs _________
Absorbance VS Wavelength. The greater the degree of conjugation the further to the right (longer the wavelength in nm) the species will absorb.
What is responsible for the strength of a bond?
Coulomb's Law:
+ and - charges attract
- and - charges repel
Bond length is determined by...
the distance b/w the nuclei that yields the lowest energy state
Rank the following according to decreasing bond length: triple bonds, double bonds, single bonds
1) triple bonds (strongest)
2) double bonds bond
3) single bonds (weakest)
sigma bond
the FIRST bond formed b/w two elements
i.e. a single bond, or the first bond of a double or triple bond
pi bond
the SECOND and THIRD bonds b/w elements
As the radius of either atom increases (larger elements), the orbitals _________ resulting in less overlap and a ________ bond.
spread apart, weaker
ex. C=N is weaker than C=O
sigma bonds: rotation? strength? stability? reactivity?
-allow for rotation
-stronger (just the sigma is stronger but a single bond is still weaker than double bond)
-more stable
-less reactive
pi bonds: rotation? strength? stability? reactivity?
-prevent rotation
-weaker (just the pi bond is weaker but double bond is still stronger than single bond)
-less stable
-more reactive
If a molecule does not have a lone pair of electrons it can't form coordinate covalent bonds with metals or other Lewis acids?
true
The Octet Rule
Atoms tend to gain or lose electrons to obtain exactly eight electrons in their valence shell. This is the highly stable "noble gas configuration".
exceptions to Octet Rule
1. Hydrogen and Helium are stable with only 2 e⁻'s in their valence shells (ex. H₂)
2. Boron and Beryllium are stable with only 6 e⁻'s in their valence shells (ex. BF₃)
3. Any atom from the third period or lower can accept more than 8 e⁻'s (ex. PCl₅, SF₆, PO₄³⁻ and SO₄²⁻)
Valence
How many bonds an atom "normally" makes.
C family = tetravalent
N family = trivalent
O family = divalent
F family = monovalent
Formal charge
The difference b/w the # of electrons in an atom's valence shell when in it's ground/elemental state and the number assigned to it in a molecule.
Formal charge= valence - assigned
High stability= ? heat of combustion
low heat of combustion
Low stability= ? heat of combustion
high heat of combustion
Resonance
-A "snapshot" of the different arrangements of electrons that contribute to the actual structure.
-The actual structure is a weighted average (hybrid) of all the contributors.
-The actual structure does NOT resonate back and forth b/w forms; it is a permanent hybrid of all the contributing structures
Lewis dot structure
Diagram of a molecule using dots to represent valence electrons.
Line-bond formula
Abbreviates the carbon atoms and shows only the ZigZag pattern of bonds from carbon atom to carbon atom. (/\/\/\/\)
Line-wedge formula
The black wedge is assumed to be coming out of the page, the dashed wedge is assumed to be going into the page, and the lines are assumed to be in the plane of the page.
Condensed formula
CH3(CH2)2CH3 To show the outline of the structure.
Fischer projection
A method for drawing an asymmetric carbon atom as a cross. The carbon chain is kept along the vertical, with the IUPAC numbering from top to bottom. Vertical bonds project away from the viewer, and horizontal bonds project toward the viewer.
Newman projection
The view seen by orienting a molecule so that neighboring atoms eclipse each other.
Ball & stick model
A molecular model in which atoms are represented by balls and bonds by sticks. The advantage of this type of model is that one can see the orientation of the atoms and bond types.
Space filling model
A molecular model in which atoms and their electron clouds are represented by spheres. The advantage is that it better represents the overlap of the electron clouds that occur in a molecule.
Chair/half-chair/boat/twist confirmations
The molecule can easily switch between these conformations, and only two of them — chair and twist-boat — can be isolated in pure form.
Which of the models is the most accurate visual representation of an actual molecule?
Space filling model?
The H-O-H bond angle in water is measured experimentally to be 104.4 degrees. The related angle H-N-H in ammonia is expected to be:
Larger due to the greater electron repulsion in water.
Isomers
Compounds with the same formula but different structure.
What is the maximum number of optically active stereoisomers for any compound?
2ⁿ, where n is the number of chiral centers.
Conformational Isomers
Molecules with the same molecular formula, the same connectivity, and can be converted by rotation about single bonds. These are not true isomers!
Structural Isomers
Compounds that have the same molecular formula but differ in the covalent arrangements of their atoms. 2-methylpentane and 3-menthypentane are both C6H14.
Stereoisomers
Molecules that have the same structural formulas and bonding patterns but different arrangements of atoms in space.
Enantiomers
Nonsuperimposable stereoisomers that are mirror images of each other. Enantiomers differ in configuration at every chiral center but share the same chemical and physical properties in a nonstereospecific environment. Optical activity is different.
Chirality
The condition in which a molecule is not superimposable on its mirror image, meaning that there is no way to rotate the atoms around their bonds in order to make it identical to its mirror image. Often referred to as "handedness."
Absolute Configuration
R(clockwise) or S(Counterclockwise)- way to physically describe the orientation of atoms about a chiral center. How two enantiomers are distinguished.
Relative configuration
The experimentally determined relationship between the configurations of two molecules, even though the absolute configuration of either may not be known.
Observed rotation
The number of degrees through which a compound rotates the plane of polarized light.
Polarimeter
An optical device used to measure the rotation of the plane of vibration of polarized light.
Plane-polarized light
Light that has been passed through a polarizing filter, allowing only the transmission of waves containing electric field vectors parallel to the lines of the filter.
Optically active
Substances that rotate the plane of polarized light. The amount of polarized light is rotated by a solution table sugar depends on its concentration.
Optically inactive
No single molecular orientation is favored and the net result is no rotation of the plane of the electric field
Racemic mixture
A mixture that contains equal amounts of the (+) and (-) enantiomers. Racemic mixtures are not optically active.
Dextrorotary
Enantiomer that rotates light to the Right; Clockwise; +
Levorotary
Enantiomer that rotates light to the Left; Counterclockwise; -
Can an optically inactive compound rotate plane-polarized light?
No
Remember the following regarding enantiomers:
1. They have opposite R/S configurations at EVERY chiral carbon.
2. They rotate place polarized light to the same degree, but in different directions.
3. They have all the same physical properties (bp, reactivity, etc.) EXCEPT for: a) how they rotate plane polarized light and b) the products they form when reacted with another chiral compound.
Diastereomers
Stereoisomers that are not mirror images of each other. Diastereomers differ in their configurations in at least one chiral center and share the same configuration in at least one chiral center. They have the same chemical properties but different physical properties.
Geometric Isomers
Compounds that have the same molecular formula but differ in the spatial arrangements of their atoms.
Cis=same side
Trans=opposite sides
Epimers
Isomers differing in configuration at only one stereogenic center.
Anomers
Cyclic stereoisomers differing in configuration at the hemiacetal carbon (C1). In a 6-membered ring, if the hydroxy group attached to C1 and the substituent attached to C5 are trans, the molecule is referred to as the α anomer. If both groups are cis, the molecule is reffered to as ß anomer. C1 and C5 are carbons adjacent to the oxygen in the ring.
E/Z convention
When the two groups attached to each carbon of the double bond are assigned priority.
Z=same side
E=opposite side
Remember the following when regarding geometric isomers:
1. Cis isomers have a dipole moment, but trans do NOT.
2. Cis isomers often experience "steric hinderance," resulting in a higher energy molecule, but trans do NOT.
Which version of 2,3-dibromo-2-butene would have the higher heat of combustion, the cis isomer or the trans isomer? Which would have the higher boiling point?
Cis?
Meso compounds
Two or more chiral centers that contain a plane of symmetry. Optically inactive. However, not all molecules with a plane of symmetry are meso.
Are meso compounds diastereomers or enantiomers? Why or why not?
?
An unknown molecule has an absolute configuration of S and rotates plane-polarized light 15 degrees in the clockwise direction. What is the absolute configuration of the enantiomeric molecule and which way does it rotate?
Absolute configuration is R; rotates plane-polarized light 15 degrees; levorotary
Resonance
-A "snapshot" of the different arrangements of electrons that contribute to the actual structure.
-The actual structure is a weighted average (hybrid) of all the contributors.
-The actual structure does NOT resonate back and forth b/w forms; it is a permanent hybrid of all the contributing structures
The individual structure that contributes the MOST to the actual structure is the one that...
1) Has the least charge (no charge better than some charge)
2) Has the least separation of charge (charges separated by 1 atom better than separated by multiple atoms)
If both species have resonance, the more stable species is...
the one with the most possible resonance structures (i.e. ClO₄⁻ is more stable than ClO₃⁻)
Aromatic compounds
circular, conjugated, unsaturated systems that are very stable, even more stable than any conjugated system
Huckel's Rule
to exhibit aromaticity, a ring system must have exactly 4n+2 pi electrons
alkane
C-C (all single bonds)
alkene
C=C (has a double bond)
alkyne
C≡C (has triple bond)
alcohol
-OH
ether
R-O-R, has two hydrocarbon groups linked by an oxygen atom
ester
R-C(=O)-O-R
amine
-NH₂
aldehyde
R-C(=O)-H
ketone
R-C(=O)-R
alkoxy
-OR
alkyl
-CH
carbonyl
-C=O
hydroxyl
-OH
acetyl
R-C(=O)CH₃
geminal (prefix gem-)
refers to the relationship between two functional groups that are attached to the same atom
vicinal (prefix vic-)
refers to the relationship between two functional groups that are attached to adjacent atoms
mesyl group
-SO₂CH₃
tosyl group
-SO₂C₆H₄CH₃
carboxylic acid
R-C(=O)OH
amide
R-C(=O)NH₂
anhydride
R-(C=O)-O-(C=O)-R
aryl
-phenyl
benzyl
-CH₂-phenyl
hydrazine
N₂H₄
vinyl
-CH=CH₂
allyl
-CH₂CH=CH₂
nitrile
-C≡N
epoxide
CH₂-O-CH₂ ring
imagine a triangle with an O at the top
enamine
-C=C-NH₂
acyl
-CH₃C(=O)-R
aromatic
benzene ring
aliphatic
CH₃-CH₂-CH₂-CH₂-CH₂-CH₃, having carbon atoms linked in open chains with NO benzene rings
sulfone
R-S(=O)(=O)-R
"crab eyes"
nitro
-NO₂
acetal
R-CH(OR)₂
http://tonga.usip.edu/gmoyna/biochem341/acetal_ketal.gif
ketal
R-C(OR)(OR)-R
http://tonga.usip.edu/gmoyna/biochem341/acetal_ketal.gif
hemiacetal
R-CH(OR)(OH)
http://tonga.usip.edu/gmoyna/biochem341/acetal_ketal.gif
hemiketal
R-C(OR)(OH)-R
http://tonga.usip.edu/gmoyna/biochem341/acetal_ketal.gif
meth-
1 (CH₃)
eth-
2 (CH₂-CH₂)
prop-
3 (CH₃-CH₂-CH₃)
but-
4 (CH₃-CH₂-CH₂-CH₃)
pent-
5 (CH₃-CH₂-CH₂-CH₂-CH₃)
hex-
6 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₃)
hept-
7 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃)
oct-
8 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃)
non-
9 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃)
dec-
10 (CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃)
sec-butyl
R-CH-CH₃(CH₂CH₃)
"butane on a stick"
isopropyl
R-CH(CH₃)₂
"peace sign on a stick"
isobutyl
R-CH₂-CH(CH₃)₂
tert-butyl
R-C(CH₃)₃
"broomstick"
IUPAC (naming) Rules
1. Find the longest carbon chain (if there is a tie, one w/ more substituents wins)
2. The terminal carbon closest to a substituent is numbered #1
3. Order the substituents alphabetically and give each one a number to match the carbon it is attached to
4. If more than one substituent use di, tri, tetra, etc. (ex. 2,2- dimethylbutane)
5. Hyphens are placed before and after substituent numbers but NOT b/w prefixes
6. Don't consider prefixes (di-,tri-, etc.) when alphabetizing or prefixes with hyphens (sec-,tert-, etc.). Do include other prefixes such as isopropyl, isobutyl, etc.
Draw 1-Bromo-2-Chlorocyclohexane
Should have a 6 carbon ring with a Br on one carbon and a Cl on the carbon next to it
hybridization
atoms, when bonded, hybridize (mix) their higher and lower energy valence electron orbitals to form "hybrid orbitals" with intermediate energy
How do you determine the hybridization number?
Count the number of sigma bonds and add the number of pairs of unbonded electrons.This number will equal the sum of the superscripts (ex. sp, sp², sp³, sp³d, spd²)
What is the percent s character of oxygen in water?
googled it and was unsuccessful :(
Valence Shell Electron Pair Repulsion Theory (VSEPR)
The theory that predicts which shape molecules will take due to the repulsion of lone pairs of electrons.
sp (shape)
linear [180°]
sp² (shape)
trigonal planar or bent [120°]
sp³ (shape)
tetrahedral, trigonal pyramidal or bent [109.5°]
sp³d (shape)
trigonal bipyramidal, seesaw, T-shaped or linear [90°/120° or 180°]
sp³d² (shape)
octahedral, square pyramidal or square planar [90°]
Scalars have only ________.
magnitude
Vectors have both _________ and _________.
magnitude and direction
Vector or scalar? mass
scalar
Vector or scalar? temperature
scalar
Vector or scalar? velocity
vector
Vector or scalar? speed
vector
Vector or scalar? displacement
vector
Vector or scalar? acceleration
vector
Vector or scalar? force
vector
Vector or scalar? work
scalar
Vector or scalar? energy
scalar
Vector or scalar? charge
scalar
Vector or scalar? electric field
scalar
Vector or scalar? magnetic field
vector
Vector or scalar? time
scalar
Vector or scalar? density
scalar
Vector or scalar? torque
vector
The product of two vectors is always a vector?
true
The product of a vector and a scalar is always a vector?
true
A rock is thrown into the air at an angle of 60° to the horizontal at a velocity of 40 m/s. Resolve this vector into its vertical and horizontal components.
...
Force
any influence capable of causing a mass to accelerate
What units are included in a Newton?
N = kg* m/s²
the amount of net force required to accelerate a mass of one kilogram at a rate of one meter per second squared
Newton's First Law
The velocity of a body remains constant unless the body is acted upon by an external force.
Inertia
the ability of an object to resist a change to its velocity
Center of mass definiton? equation?
a weighted average of mass distribution
Cmass = (r1m1 + r2m2 + r3m3 ...)/mtotal
r is the displacement vector b/w a reference pt and each mass
Center of gravity
at the center of mass
Center of buoyancy
always at the geometric center, irrespective of the center of mass
Newton's Second Law
F=ma
The acceleration a of a body is parallel and directly proportional to the net force F and inversely proportional to the mass m
A constant force will cause an object to accelerate faster and faster?
false
A constant force will cause a constant (non-changing) acceleration
You can accelerate a ball horizontally across the room by throwing it?
false
The ball is only accelerating while it is in contact with your hand
A thrown ball is always accelerating in the vertical direction until it contacts the ground?
true
It is always under the influence of the gravitational field
Newton's Third Law
Action-Reaction
Whenever one object creates (via contact or is responsible for) a force on a second object, the second object always exerts an equal and opposite force on the first object.
The moon is approximately 400 times smaller than the sun. If the sun exerts a gravitational force of F on the moon, what is the approximate force exerted on the sun by the moon, in terms of F?
(Assume equal densities)
...
Displacement
the shortest distance b/w point A and point B
What is the difference b/w distance and displacement?
...
How does distance change as a car drives around a circular track? How does displacement change?
...
Can you use D = rt to calculate displacement?
...
When you see "Constant Velocity" or "Constant Speed" think...
1. No acceleration
2. No NET force
3. All forces sum to zero
(up forces=down forces, right forces=left forces)
4. No change in direction
5. The object is in equilibrium
Acceleration is any change in ________.
velocity
If there is no net force, there is no acceleration?
true
If the force increases, acceleration increases?
true
If there is no acceleration there is no force?
true
Steps to interpret linear motion graphs.
1. What does the slope represent?
2. Is this slope positive or negative? What does this tell you?
3.Is the slope constant (straight line) or non-constant (curved line)? What does this tell you?
4.What value is on the y-axis?
5. Is the y value positive or negative (above or below x-axis)? What does this tell you?
What happens to a particle as you cross the x-axis?
...
What happens to a particle at a corner?
...
What happens to a particle at a flat horizontal line on a velocity vs. time graph?
...
What happens to a particle at a flat horizontal line on a displacement vs. time graph?
...
If a ball is going up, it ___________ of velocity each second.
loses 10 m/s
If a ball is going down, it _________ of velocity each second.
gains 10 m/s
If a projectile has an initial vertical velocity of 30 m/s, how many seconds will it take to reach its max height?
3 secs
If a projectile has an initial velocity of 60 m/s at an angle of 30° from the horizon, how many seconds will it be in the air?
sin30 = 0.5
0.5 x 60m = 30 m up and 30 down
so 3 secs up and 3 secs down
which is 6 secs total
average velocity
Vavg = (V₁ + V₂)/2
If a projectile has a vertical velocity of 100 m/s, how many secs will it take to reach max height and what will its average velocity be?
10 secs to reach max height
(100 + 0)/2 = 50 m/s average
Equation for calculating distance traveled?
D = rt
If a projectile has an initial vertical velocity of 30 m/s, how long will it be in the air, how high will it go, and what will be its average velocity during the entire trip?
6 secs in the air
30 meters high
15 m/s average velocity
range equation
Range = Vx × time
When you see projectiles think...
1. Horizontal velocity never changes (ignoring air resistance)
2. Horizontal acceleration always = 0
3. Vertical acceleration always = 10 m/s²
4. Vertical behavior is exactly symmetrical (upward trip is identical to downward trip)
5. Time in the air depends on the vertical component of velocity only
6. Range depends on both the vertical and horizontal components
7. Time is always the same for both the x and y components of the motion
If a man on a cliff first fires a gun straight down toward the ground below; and then fires a second round straight up into the air, which will hit the ground with the greater velocity?
They hit with the same velocity because they will both terminal velocity
total time in air equation
Tair = 2V/g
air resistance
the force exerted on projectiles or falling bodies due to actual physical collisions with air molecules
greater surface area = _______ air resistance
more
less aerodynamic = _________ air resistance
more
rough surface = _________ air resistance
more
greater velocity = _________ air resistance
more
At terminal velocity...
Fair = mg
Two skydivers, one of mass 100kg and the other of mass 150kg fall towards earth.
Who reaches terminal velocity first?
How will their terminal velocities compare?
Who will hit the ground first?
150kg reaches first
100kg= slower terminal velocity, 150kg= higher terminal
150kg hits ground first
What will be the terminal velocity of an object falling in a vacuum?
There is no terminal velocity because there is no air resistance pushing back on the object.
One projectile is launched in a vacuum and a second projectile is launched in the presence of air resistance. Both projectiles are given identical initial velocities and launch angles. What will be the differences in range, max height and final velocity for the two projectiles?
In vacuum:
higher range
greater max height
greater final velocity
In air:
lower range
lower max height
lower final velocity
sin 0
0
sin30
½
sin45
√2/2 or 0.7
sin60
√3/2 or 0.9
sin90
1
cos 0
1
cos30
√3/2 or 0.9
cos45
√2/2 or 0.7
cos60
½
cos90
0
1/2
0.5
1/3
0.33
1/4
0.25
1/5
0.2
1/8
0.125
√2
1.41
√3
1.73
√5
2.23
√6
2.45
√7
2.65
√8
2.83
√10
3.16
√11
3.32
√12
3.46
√13
3.61
√14
3.74
√15
3.87
area of a circle
A= π r²
circumference of a circle
C= 2π r
or
2π r
area of a triangle
A= ½bh
volume of a sphere
V= 4/3π r³
surface area of a sphere
A= 4π r²
Pythagorean theorem
a² + b² = c²
PS and BS Timing Chart
I 62 58
II 54 50 46
III 46 42 38
IV 38 34 30
V 30 26 22
VI 22 18 14
VII 14 10 6
VB Timing Chart
I 52
II 44
III 36
IV 28
V 20
VI 12
VII 4
Scientific notation rules- Do what with exponents?
Addition
Subtraction
Multiplication
Division
Square root
( )^x
Add- make exp the same, add numbers
Subt- make exp the same, subtract numbers
Mult- add exp
Divide- subtract exp
Square root- take √ of matissa, mult exp by ½
( )^x- matissa^x, mult exp
deci
10^-1
centi
10^-2
milli
10^-3
micro
10^-6
nano
10^-9
pico
10^-12
femto
10^-15
deca
10¹
hecto
10²
kilo
10³
mega
10⁶
giga
10⁹
tera
10^12
What is the square root of 75?
√81= 9 and √64= 8
so around 8.7
Change 24/45 to a decimal.
think 25/50
so around 0.5
What is the square root of 120?
11² is 121
so the √120 is about 11
What is the decimal equivalent for 3/13?
think 2/10 which is 0.2
so 3/13 is around 0.2
Change 2/7 to a decimal.
think 2/6 which is 0.3 and 2/8 which is 0.25
so 2/7 is around 0.28
What is the decimal equivalent of 16/3?
think 15/3 which is 5
so 16/3 is around 5.3
What is the cube root of 25?
think 3³ which is 27
so ³√25 is around 2.9
How do you simplify if you end up with something like 0.05 x 10^-2 or 220 x 10^12?
0.05 x 10^-2 = 5 x 10^-4
220 x 10^12 = 2.2 x 10^14
How do you write a small whole number, such as 5, in scientific notation?
5x10⁰
sin∅ = ?
opp/hyp
cos∅ = ?
adj/hyp
tan∅ = ?
opp/adj
inverses of sin, cos, and tan?
cosecant, secant, cotangent
tan∅ = ?/?
tan∅ = sin∅/cos∅
sin²x + cos²x = 1
...
All of the angles of a triangle must add up to _____?
180°
π radians = ?°
180°
2π radians = ?°
360°
Recognizing non-linear graphs...
If two variables are both in an equation, and one of them contains an exponent, log, ln, or root, the graph of either variable vs. the other will yield a non-linear graph.
Recognizing linear graphs...
If BOTH variables contain the exact same math (i.e. both are cubed, or both are square rooted), the graph of one versus the other will be linear.
shape of y = x
...
shape of y = 1/x
...
shape of y = x²
...
shape of y = x³
...
shape of y = √x
...
shape of y = lnx
...
shape of y = sin x
...
shape of y = cos x
...
Which are non-linear? X = ½at²
X vs t
t vs X
a vs t
t vs a
Which are linear? X = ½at²
X vs a
a vs X
Which are non-linear? V = √(2gh)
V vs g
Which are linear? V = √(2gh)
g vs h (both are under the square root)
Nucleolus
The nucleolus (plural nucleoli) is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA (rRNA) is transcribed AND assembled within the nucleolus.

the dual bi-layer membrane (4 layers) is continuous with teh ER and contains nuclear pores
Rough ER
covered with ribosomes; all proteins not bound for the cytosol are made here

The bi-layer nucleus membane is continues with the ER
Smooth ER
Lipid synthesis/modification (but NOT lipid metabolism; many students get this confused. Lipids are MADE at the ER but METABOLIZED in the mitochondria).
Golgi Apparatus
The cellular "post-office;" organize, package, modify, excrete, etc.
Mitochodria
Have there own DNA and are passed down through the maternal lineonly

evolved from aerobic prokaryotes in symbiosis with a eukaryotic cell
How do the pH values of the matrix and the intermembrane space compare?
The intermembrane space tends to have a low pH because of the proton gradient which results when protons are pumped from the mitochondrial matrix into the intermembrane space during electron transport.
Centrioles/Centrosome
the centrosome is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell-cycle progression

Centrosomes are composed of two orthogonally arranged centrioles surrounded by an amorphous mass of protein responsible for microtubule nucleation and anchoring.

In general, each centriole of the centrosome is based on a nine triplet microtubule assembled in a cartwheel structure
Lysosomes
PH of 5, digest cell parts, fuse with phagocytotic vesicles, participate in cell death (apoptosis), etc.;

form by budding off from the Golgi.
Peroxisomes
Self-replicate, detoxify chemicals, participate in lipid metabolism
A certain genetic enineering experiment requires a lab worker to inject a segment of DNA into the nucleus of a living cell. To access the nuclear lumen, the microscopic needle must pierce a minimum of how many layers of lipid membrane?
6
Tubulin
Tubulin is one of several members of a small family of globular proteins. The most common members of the tubulin family are α-tubulin and β-tubulin, the proteins that make up microtubules
cytoskeleton
The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein
spindle apparatus
refers to the subcellular structure that segregates chromosomes between daughter cells during cell division. It is also referred to as the mitotic spindle during mitosis or the meiotic spindle during meiosis
Actin
Actin is a globular protein that is the building block of two types of filaments in cells:

1)microfilaments - one of the three major components of the cytoskeleton

2)thin filaments - part of the contractile apparatus in muscle cells.

Thus, actin participates in many important cellular processes including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the establishment and maintenance of cell junctions and cell shape.
Myosin
Myosins comprise a family of ATP-dependent motor proteins and are best known for their role in muscle contraction and their involvement in a wide range of other eukaryotic motility processes

Multiple myosin II molecules generate force in skeletal muscle through a power stroke mechanism fuelled by the energy released from ATP hydrolysis.
Flegella vs Cilia
Cilia are short and there are usually many (hundreds) cilia per cell. On the other hand, flagella are longer and there are fewer flagella per cell (usually one to eight).

Though eukaryotic flagella and motile cilia are structurally identical, the beating pattern of the two organelles can be different. The motion of flagella is often undulating and wave-like, whereas the motile cilia often perform a more complicated 3D motion with a power and recovery stroke.
In humans, cilia are found exclusively in the:
Respiratory system (lungs)
Nervous System (ependymal cells-make CSF)
Reproductive System (Fallopian tubes)
Where are microtubules found?
in all the cilia, in the flegella of sperm and in the cells as part of teh spindle apparatus.
What problems would a disease that prevented microtubule production cause?
Can't get dust out of the lungs→bronchitis
get reproduce (cilia in fallopian tubes and sperm flegella)
CSF wont flow
Eukaryotic vs. Prokaryotic Flegella
Eukaryotic=whipping motion; microtubules made of tubulin

Prokaryotic=spinning/rotating motion; simple helices made of flagellin
Types of Cellular Junctions
Tight Junctions: water-proof barriers

Gape Junctions: tunnels allowing exchange

Desmosomes: strongest of the cellular junctions; they wild cells together, protecting against stress, but are NOT watertight barriers
Where would you find Tight Junctions?
They prevent the passage of molecules and ions through the space between cells. So materials must actually enter the cells (by diffusion or active transport) in order to pass through the tissue. This pathway provides control over what substances are allowed through. (Tight junctions play this role in maintaining the blood-brain barrier).
Where would you find Gap Junctions?
Gap junctions are particularly important in cardiac muscle: the signal to contract is passed efficiently through gap junctions, allowing the heart muscle cells to contract in tandem.

Gap junctions are expressed in virtually all tissues of the body, with the exception of adult fully developed skeletal muscle and mobile cell types such as sperm or erythrocytes.

Several human genetic disorders are associated with mutations in gap junction genes. Many of those affect the skin because this tissue is heavily dependent upon gap junction communication for the regulation of differentiation and proliferation.
Where would you find Desmosomes?
Desmosomes help to resist shearing forces and are found in simple and stratified squamous epithelium
Phospholipids
Phospholipids are a class of lipids that are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline
Integral Proteins
An integral membrane protein (IMP)

a protein molecule (or assembly of proteins) that is permanently attached to the biological membrane.

IMPs comprise a very significant fraction of the proteins encoded in an organism's genome.[1]
All transmembrane proteins are IMPs, but not all IMPs are transmembrane proteins
Transport Proteins
a protein which serves the function of moving other materials within an organism
Cholesterol
an organic chemical substance classified as a waxy steroid of fat. It is an essential structural component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and vitamin D.

Cholesterol is the principal sterol synthesized by animals, predominantly in the liver
Membrane receptors
specialized integral membrane proteins that take part in communication between the cell and the outside world
Fluid mosaic model
The plasma membrane is described to be fluid because of its hydrophobic integral components such as lipids and membrane proteins that move laterally or sideways throughout the membrane. That means the membrane is not solid, but more like a 'fluid'
exocytosis
process by which a cell directs the contents of secretory vesicles out of the cell membrane
endocytosis
is a process by which cells absorb molecules (such as proteins) by engulfing them
Phagocytosis
a specific form of endocytosis involving the vesicular internalization of solid such as bacteria, and is, therefore, distinct from other forms of endocytosis such as the vesicular internalization of various liquids. Phagocytosis is involved in the acquisition of nutrients for some cells, and, in the immune system, it is a major mechanism used to remove pathogens and cell debris. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytosed
Pinocytosis
a form of endocytosis in which small particles are brought into the cell—forming an invagination, and then suspended within small vesicles that subsequently fuse with lysosomes to hydrolyze, or to break down, the particles

Pinocytosis also works as phagocytosis, the only difference being that phagocytosis is specific in the substances it transports. Phagocytosis actually engulfs whole particles, which are later broken down by enzymes, such as lysosomes, and absorbed into the cells. Pinocytosis, on the other hand, is when the cell engulfs already-dissolved or broken-down food.
Secondary Active Transport
In secondary active transport or co-transport,does not uses energy to transport molecules across a membrane; however, in contrast to primary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of the cell is used.

E.g., in a mitochondria, H⁺ is pumped out of the matrix and then flows back in through turbin thing
Epithelial tissue
Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport and detection of sensation. In Greek "Epi" means, "on, upon," and "Theli" meaning "tissue." Epithelial layers are avascular, so they must receive nourishment via diffusion of substances from the underlying connective tissue, through the basement membranes

Simple epithelium is one cell thick, that is, every cell is in direct contact with the underlying basement membrane. It is generally found where absorption and filtration occur. The thinness of the epithelial barrier facilitates these processes

Example of an epithelial cell - squamous cells
Nervous tissue
It is composed of neurons, which transmit impulses, and the neuroglia cells, which assist propagation of the nerve impulse as well as provide nutrients to the neuron.
Connective tissue
Although connective tissue exists in a number of forms, all types have three basic structural elements -- cells, fibres and intercellular substance

Connective tissue makes up a variety of physical structures including, tendons and the connective framework of fibers in muscles, capsules and ligaments around joints, cartilage, bone, adipose tissue, blood and lymphatic tissue
Muscle tissue
Muscle is a very specialized tissue that has both the ability to contract and the ability to conduct electrical impulses.

Muscles are are classified both functionally as either voluntary or involuntary and structurally as either striated or smooth. From this, there emerges three types of muscles: smooth involuntary (smooth) muscle, striated voluntary (skeletal) muscle and striated involuntary (cardiac) muscle.
What type of tissue is blood?
Connective tissue
What type of tissue is the dermis?
Epithelial tissue
What type of tissue are adipocytes?
Connective tissue
Intercelular Communication
Endocrine System: Slow, general, long-lasting

Nervous System: Fast, specific, short-lived

Paracrine System: local mediator hormones only (form of cell signalling in which the target cell is near the signal-releasing cell)
What is the purpose of chromosomes?
to efficiently package the very long DNA strands so they can easily be stored between divisions and moved during division
Histones
histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long
Nucleosomes
Nucleosomes are the basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound around a histone protein core. This structure is often compared to thread wrapped around a spool.
Chromatin
Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell
Diploid
A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father. In a diploid state the haploid number is doubled, thus, this condition is also known as 2n
Haploid
The haploid number (n) is the number of chromosomes in a gamete. A somatic cell has twice that many chromosomes (2n).
Homologous
chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father.[1] They are usually not identical
Sister Chromatids
Sister chromatids are two identical copies of a chromatid connected by a centromere. Compare sister chromatids to homologous chromosomes, which are the two different copies of the same chromosome that diploid organisms (like humans) inherit, one from each parent. In other words, sister chromatids contain the same genes and same alleles, and homologous chromosomes contain the same genes but two copies of alleles, each of which might or might not be the same as each other. A full set of sister chromatids is created during the S subphase of interphase, when all the DNA in a cell is replicated. Identical chromatid pairs are separated into two different cells during mitosis, or cellular division.
Cetromere
A centromere is a region of DNA typically found near the middle of a chromosome where two identical sister chromatids come closest in contact. It is involved in cell division as the point of mitotic spindle attachment. The sister chromatids are attached all along their length, but they are closest at the centromere.
Cell Cycle
Draw the cell cycle pie chart that includes G₁, G₂,G₀,S, and M phases
Why is the G₀ phase of the cell cycle particularly significant?
A resting phase where the cell has left the cycle and has stopped dividing.

Cells that have temporarily or reversibly stopped dividing are said to have entered a state of quiescence called G₀ phase.
How many chromosomes are there before replication?
46
How many chromosomes are there after replication?

and what is relative mass of DNA to the mass of DNA before?
46
2x
How many chromosomes are there during the interphase?
46
How many chromosomes are there before S-phase?
46
How many chromosomes are there after S-phase?

and what is relative mass of DNA to the mass of DNA before?
46
2x
How many chromosomes are there in a diploid cell?
46
How many chromosomes are there in a haploid cell?
23
Interphase
made up of the G₁, S, & G₂ phases

Interphase is the phase of the cell cycle in which the cell spends the majority of its time and performs the majority of its purposes including preparation for cell division. In preparation for cell division, it increases its size and makes a copy of its DNA. Interphase is also considered to be the 'living' phase of the cell, in which the cell obtains nutrients, grows, reads its DNA, and conducts other "normal" cell functions. The majority of eukaryotic cells spend most of their time in interphase. Interphase does not describe a cell that is merely resting but is rather an active preparation for cell division. A common misconception is that interphase is the first stage of mitosis. However, since mitosis is the division of the nucleus, prophase is actually the first stage
S-phase
S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase
What happens in Prophase? And how many chromosomes are present?
Chromatin fibers become coiled into chromosomes with each chromosome having two chromatids joined at a centromere.

The mitotic spindle, composed of microtubules and proteins, forms in the cytoplasm.

The mitotic spindle initially appears as structures called asters which surround each centriole pair.

The two pair of centrioles (formed from the replication of one pair in Interphase) move away from one another toward opposite ends of the cell due to the lengthening of the microtubules that form between them.

In late prophase:
The nuclear envelope begins to break up.

Polar fibers, which are microtubules that make up the spindle fibers, reach from each cell pole to the cell's equator.

Kinetochores, which are specialized regions in the centromeres of chromosomes, attach to a type of microtubule called kinetochore fibers.

The kinetochore fibers "interact" with the spindle polar fibers connecting the kinetochores to the polar fibers.

The chromosomes begin to migrate toward the cell center


46 chromosomes are present
What happens in Metaphase? And how many chromosomes are present?
The nuclear membrane disappears completely.

The two pair of centrioles align at opposite poles of the cell.

Polar fibers (microtubules that make up the spindle fibers) continue to extend from the poles to the center of the cell.

Chromosomes move randomly until they attach (at their kinetochores) to polar fibers from both sides of their centromeres.

Chromosomes align at the metaphase plate at right angles to the spindle poles.

Chromosomes are held at the metaphase plate by the equal forces of the polar fibers pushing on the centromeres of the chromosomes.

46 chromosomes are present
What happens in Anaphase? And how many chromosomes are present at?
The paired centromeres in each distinct chromosome begin to move apart.

Once the paired sister chromatids separate from one another, each is considered a "full" chromosome. They are referred to as daughter chromosomes.

Through the spindle apparatus, the daughter chromosomes move to the poles at opposite ends of the cell.

The daughter chromosomes migrate centromere first and the kinetochore fibers become shorter as the chromosomes near a pole.

In preparation for telophase, the two cell poles also move further apart during the course of anaphase. At the end of anaphase, each pole contains a complete compilation of chromosomes

92 chromosomes are present
What happens in Telophase? And how many chromosomes are present?
The polar fibers continue to lengthen.

Nuclei (plural form of nucleus) begin to form at opposite poles.

The nuclear envelopes of these nuclei are formed from remnant pieces of the parent cell's nuclear envelope and from pieces of the endomembrane system.

Nucleoli (plural form of nucleolus) also reappear.

Chromatin fibers of chromosomes uncoil.

After these changes, telophase/mitosis is largely complete and the genetic "contents" of one cell have been divided equally into two.
Meiosis yeilds what?
our (4) genetically distinct, haploid daughter cells
Gametes (germ cells)
a cell that fuses with another cell during fertilization (conception) in organisms that reproduce sexually
Mitosis yeilds what?
Yeilds (2) genetically identical, diploid daughter cells
How many chromotids and chromosomes are present in Prophase I?
(4c, 2n) Diploid cell
How many chromotids and chromosomes are present in Metaphase I
(4c, 2n) Diploid cell
How many chromotids and chromosomes are present in Anaphase I
(2c, n) on one side
(2c, n) on other side
How many chromotids and chromosomes are present in Telophase I
(2c, n) on one side
(2c, n) on other side
How many chromotids and chromosomes are present in Prophase II
(2c, n) Haploid cell
How many chromotids and chromosomes are present in Metaphase II
(2c, n) Haploid cell
How many chromotids and chromosomes are present in Anaphase II
(c, n) on one side
(c, n) on other side
How many chromotids and chromosomes are present in Telophase II
(c, n) on one side
(c, n) on other side
Phases of Miosis
How many chromotids and chromosomes are present after miosis
(c, n) Haploid cell
What is nondisjuction and where can it occur?
What would be the ramifications?
the failure of chromosome pairs to separate properly during meiosis stage 1 or stage 2. This could arise from a failure of homologous chromosomes to separate in meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. The result of this error is a cell with an imbalance of chromosomes
When does crossing-over occur and why is it important?
It occurs in Miosis 1 and is important because it adds more variability to the gamet's DNA
If a Karyotype were produced for a cell that had just undergone Telophase I of Meiosis, the entire karyotpe slide should contain:

a)23 pairs of homologous chromosoms, all of similar size
b)46 chromosomes, increasing in size from 1 to 23
C)92 chromosomes, decreasing in size form 1 to 92
D)23 choromosomes, decreasing in size from 1 to 23
D

Meiosis 1 takes a cell with 23 pairs of homologous chromosomes, or 46 chromosomes, and creates two cells, each with 23 non-paired, non-homologous chromosomes. You should also know that choromsomes generally decrease in size, with chromosome One being the largest.
What % of a cell's mass is due to water?
65-95%
What are the four major roles of water int he Human Body?
1) Solvent for all major reactions
2) Reactant for hydrolysis reactions (nearly all catabolic RXNs in the Body)
3) Product of nearly all synthesis reactions (e.g., dehydration synthesis)
4) Maintenance of Homeostasis (due to its high specific heat; many reaction release heat that would cause other solvents to boil)
What is the definition of a lipid
any biomolecule soluble in non-polar solvents and insoluble in polar solvents
Draw a Fatty acid in line-bond form
...
Draw a tryiacylglycerols (aka, triglyceride) in line-bond form
...
Draw a phospholipid in line-bond form
...
Draw a steroid in line-bond form
...
Draw a Glycolipid in line-bond form
...
amphipathic
a term describing a chemical compound possessing both hydrophilic (water-loving, polar) and lipophilic (fat-loving) properties.

Phospholipids are amphipathic
HISTIDINE
...
ISOLEUCINE
...
LEUCINE
...
LYSINE
...
METHIONINE
...
PHENYLALANINE
...
THREONINE
...
TRYPTOPHAN
...
VALINE
...
ALANINE
...
ARGININE
...
ASPARTIC ACID
...
CYSTEINE & CYSTINE
...
GLUTAMIC ACID
...
GLUTAMINE
...
GLYCINE
...
ORNITHINE
...
PROLINE
...
SERINE
...
TAURINE
...
TYROSINE
...
Which amino acids are polar?
Serine, Threonine, Asparagine, Glutamine
Which amino acids are non-polar?
Alanine, Valine, Isoleucine, Leucine, Methionine, Phenylalanine, Tyrosine, Tryptophan
Which amino acids are basic?
Asparic Acid, Glutamic Acid
Which amino acids are acidic?
Arginine, Histidine, Lysine
Essential vs Non-essential amino acids
9 to 12 can be manufactured by the body (estimates vary). They are called nonessential amino acids because they need not be obtained from the diet. The remaining 8 to 11, called the essential amino acids, cannot be made by the body and must be obtained from the diet
Draw a peptide bond. Name two unique characteristics of peptide bonds
the carboxyl group of one molecule reacts with the amino group of the other molecule, causing the release of a molecule of water (H2O), hence the process is a dehydration synthesis

(add picture)
What is responsible for tertiary structure
H-bonding
Ionic bond
Ionic repulsion
Disulfide bond
What determines protein folding structure?
determined by the amino acid sequence
Protein denaturing agents are...
Acid
Heat
Urea
Mercaptoethanol
IF a student has four amino acids, Clycine, Phenylalanine, Glutamine and Aspartamine, how many unique proteins can he form without using any amino acid more than once in any protein?
24

(N=4 therfore, 4*2*3*1=24)
Empirical formula for Carbohydrates
(CH₂O)n
Draw glucose in its "chain" form
...
Draw Fructose (both "ring" and "chain" form)
...
Draw the alpha anomer of glucose
...
Draw the beta anomer of glucose
...
which carbohydrates are ketones? and which are aldehydes?
Fructose = Ketone
Glucose = Aldahyde
Glycogen
Branched, alph-linked glucose polymer, used for storage in animals
Starch
Branced, alpha-linked glucose plymer, used for storage in plants
Cellulose
Beta-linked glucose plymer, used for storage in plants, indigestible to animals
Do animals use alpha polysaccharides or Beta?
Alpha
Do bacteria use alpha polysaccharides or beta?
beta
Draw the basic structure of a nucleotide and lable its parts
...
What other biomolecules, besides DNA/RNA are nucleotides
cellular signaling molecules: cGMP and cAMP

cofactors of enzymatic reactions: coenzyme A, FAD, FMN, and NADP+

sources of chemical energy: ATP and GTP
Role of vitamins
Some have hormone-like functions as regulators of mineral metabolism (e.g., vitamin D), or regulators of cell and tissue growth and differentiation (e.g., some forms of vitamin A). Others function as antioxidants (e.g., vitamin E and sometimes vitamin C).[3] The largest number of vitamins (e.g., B complex vitamins) function as precursors for enzyme cofactors, that help enzymes in their work as catalysts in metabolism.
Two theories of enzyme specificity
Lock and Key
the substrate (the key) fits exactly into the active site (the lock)

Induce to fit
the active site only fits the shape of the substrate after the substrate has bound to the enzyme.
Coenzymes
non-protein species that are NOT permanently attached to the enzyme and are required by the enzyme to function
Prosthetic Gourps
Non-protein species that are permanently attached to the enzyme and are required by the enzyme to function
Cofactors
a general term for any species required by an enzyme to function; coenzymes and prosthetic groups are both example of cofactors
Vmax in a RXN rate vs [substrate] graph
enzyme-catalysed reactions are saturable, their rate of catalysis does not show a linear response to increasing substrate. If the initial rate of the reaction is measured over a range of substrate concentrations (denoted as [S]), the reaction rate (v) increases as [S] increases, as shown on the right. However, as [S] gets higher, the enzyme becomes saturated with substrate and the rate reaches Vmax, the enzyme's maximum rate
How does pH affect reaction rate?

Draw a graph of this
...
How does temperature affect reaction rate?

Draw a graph of this
...
How does substrate concentration affect reaction rate?

Draw a graph of this
...
How does enzyme concentration affect reaction rate?

Draw a graph of this
...
Types of Enzyme Iinhibition
Competitive
Inhibitor binds at the cite site; the effect can be overcome by increasing [substrate]

Non-competitive
inhibitor binds away from the active site and changes the shape of the enzyme

Irreversible
inhibitor bonds covalently to the enzyme and permanently disable it
Zymogens
A zymogen (or proenzyme) is an inactive enzyme precursor. A zymogen requires a biochemical change (such as a hydrolysis reaction revealing the active site, or changing the configuration to reveal the active site) for it to become an active enzyme

The pancreas secretes zymogens partly to prevent the enzymes from digesting proteins in the cells in which they are synthesised. Enzymes like pepsin are created in the form of pepsinogen, an inactive zymogen
Phosphorylation/De-phosphorylation
a sequence of events where one enzyme phosphorylates another, causing a chain reaction leading to the phosphorylation of thousands of proteins.
This can be seen in signal transduction of hormone messages.
Allosteric Regulation
ezyme regulation away from the active site
What does the suffix ase mean?
anzyme
What does the suffix tase mean?
...
what does the suffice Kinase mean?
kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates, a process referred to as phosphorylation.
phophatase
A phosphatase is an enzyme that removes a phosphate group from its substrate
What is the definition of motabolism?
The sum of all chemical reactions in the body
What is the biological definition of respirations?
The breakdown of macromelucles into smaller species to harvest energy
Aerobic vs anaerobic respiration
aerobic respiration is a process that requires oxygen, but in anaerobic respiration, oxygen is not required.
Obligate aerobe vs Facultative aerobe
An obligate aerobe is an aerobic organism that requires oxygen to grow.

facultative aerobe one that can live in the presence of oxygen, but does not require it
Obligate anaerobe vs Facultative anaerobe
microorganisms that live and grow in the absence of molecular oxygen; some of these are killed by oxygen

An organism which is capable of producing energy through aerobic respiration and then switching back to anaerobic respiration depending on the amounts of oxygen and fermentable material in the environment
Where does glycolysis occur?
It occurs in the cytosol of the cell.
The overall reaction of glycolysis is:
Glucose + 2NAD⁺ + 2ADP + 2P → 2pyruvate + 2NADH + 2H⁺ + 2ATP +2H₂O
How many ATP and NADH are produced in glycoloysis?
2NADH + 2ATP

( 4ATP are created but 2 are required so the net is 2ATP)
How many ADP and NAD⁺ are required in glycoloysis?
2ADP + 2NAD⁺
What is the number of pyruvate produced per glucose in glycoloysis?
2
Substrate Level Phosphorylation vs Oxidative Phosphorylation
Substrate-level phosphorylation is a type of metabolism that results in the formation and creation of ATP or GTP by the direct transfer and donation of a phosphoryl (PO3) group to ADP or GDP from a phosphorylated reactive intermediate. By convention, the phosphoryl group that is transferred is referred to as a phosphate group.

An alternative way to create ATP is through oxidative phosphorylation, which takes place during the process of cellular respiration, in addition to the substrate-level phosphorylation that occurs during glycolysis and the Krebs cycle.

Oxidative phosphorylation is a metabolic pathway that uses energy released by the oxidation of nutrients to produce ATP
Gluconeogensis
The reversal of glycolysis
Fermentation
The sole raour for namy bacteria; used by animals only during exygen debt (i.e., during strenuous exercies)

In ethanol fermentation, ethanol is produced and is the final electron acceptor.

In lactic acid fermentations, lactate is produced and is the final electron acceptor

***Fermentation is important because it regenerates NAD⁺ so glycolysis can continue
What initially goes into the krebs cycle and what comes out
Acetyl CoA enters the Kreb cycle - 3 NADH, 1 GTP, 1 FADH₂, 2 CO₂ is generated every cycle (per acetyl CoA)

Because two acetyl-CoA molecules are produced from each glucose molecule, two cycles are required per glucose molecule. Therefore, at the end of two cycles, the products are: two GTP, six NADH, two QFADH₂, and four CO₂
What is the number of cycles per glucose in the krebs cycle?
2
a.

Draw a simplified krebs cycle chart
...
a.

Draw a diagram of electrons from the first molecule that delivers the electron to the chain, throught the entire chain, and onto the final electron acceptor
...
In the electron chain, each NADH makes how many ATP and each FADH₂ makes how many ATP
NADH=3
FADH₂=2

Some books say 2.5 and 1.5
Explain why FADH₂ produces fewer ATP
FADH₂ drops its electrons on the second protein in the chain not the first
a.

Draw a digram starting with glycolysis, how many ATP are made from from NADH and FADH₂
...
Where does Lipid Metabolism occur?
Occurs in the mitochondria; and to a limited degree in the peroxisomes

(extra long chain fatty acids cannot be metabolized by the mitochondra. Thy are sent to the peroxisomes and "chopped up" to smaller pieces. They then return and go thru the same B-oxidation pathway as other smaller fatty acids
What are the GENERAL mechanism of B-Oxidation
Carbons are removed two at time to form Actyl-CoA grops that can be fed into the Krebs cycle

Uneven carbon chains will result in a 3-carbon residue that is funneled into a separate reaction pathway
B-Oxidation
the process by which fatty acids, in the form of Acyl-CoA molecules, are broken down in mitochondria and/or in peroxisomes to generate Acetyl-CoA, the entry molecule for the Citric Acid cycle
What do we get form each 2-carbon cycle in B-Oxidation
1 FADH₂ = 2ATP
1 NADH = 3ATP
1 Acetyl-Coa = 12ATP

Total = 17 ATP
Protein Metabolism
Amino acids are broken down into acetyl-CoA and fed into the Kreb's cycle
Where can Acetyl-CoA come from that goes into the krebs cycle?
Carbohydrates, fats or proteins
What is the order in which healthy people metabolize biological molecules
Carbohydrates first, then fats, then proteins
How many calories are in one gram of fat, protein, and carbohydrates?
fat = 9
protein = 4
carbohydrates = 9
Name the proteins that an electron passes through in the electron transport chain
I → Q → III → Cyt c → IV
Based on their interaction in the Electron Transport Chain, it can be said of Complex III and Cytochrome C that:

A) Complex III has a higher oxidation potential than Cytochrome C because Complex III gets reduced

B) Complex III has a higher potential than cytochrome C because complex III gets reduced

C) Cytochrome C has a higher reduction potential than complex III because Cytochrome C gets reduced

D) Cytochrome C has a higher oxidation potential than Complex III bewcause Cytochrome C gets reduced
Answer C
A Student takes a sample of lung tissue, blends it up ,and then adds a detergent to disrupt the cell membranes. After centrifuging the sample, he notices a colored liquid on the top and a solid pellet at the bottom. Which of the following is most likely the major component of the liquid layer?

A) Cellular organells
B) Proteins
C) cytosol
D) water
D; Water is the major component of all cells, comprising about 70%. Organelles and proteins will be more dense than water and will settle to the bottom forming the pellet. Cytosol is defined as the liquid inside the cell along with all of its proteins and organelles, thus water is the best answer.
Which of the following functional groups in NOT found in a triacylglycerol molecule?

A. alkane
B. ester
C. carbonyl
D. carboxylic acid
D. carboxylic acid.

There IS a carboxylic acid functional group in a FATTY ACID, but not in a triacylglycerol because it has been changed to an ester.
The amino acid Glutamate is titrated with base to study the pKa's of various hydrogens on the amino acid. Which of the following gives the correct order of hydrogen abstraction proceeding from low to high pH?

A. Hydrogen on the R-group, carboxylic acid group hydrogen, amine group hydrogen.

B. Carboxylic acid group hydrogen, hydrogen on the R-group, amine group hydrogen

C. Carbosylic acid group and R-group hydrogen at approximately the same pH, followed by the amine group hyrdrogen

D. Carboxylic acid group hydrogen, amine group hydreogen, hydrogen on the R-group
B; With almost no exceptions, the order of decreasing acidity (meaning the most acidic hydrogen will come off first, followed by progressively less acidic hydrogens) is as follows: 1) The carboxylic acid hydrogen comes off first. You may recall that it is always gone at cellular pH and thus usually drawn as the ion; 2) Any acidic hydrogen on the R-group will come off next. Glutamate has an acidic hydrogen on the carboxylic acid; 3) the amine group hydrogen will come off last, and only at a very basic pH. You may also note that at cellular pH an amino acid is always drawn with an NH3+ group, not an NH2 group.
Which of the following does NOT contribute to the tertiary level of protein folding?

A. Proine turns
B. Covalent bonds
C. Alpha helices
D. Intermolecular repulsions
C; All of the following contribute to tertiary protein folding: hydrogen bonding, hydrophobic interactions, ionic interactions, proline turns, Van der Walls forces and disulfide bonds. This is a good test to see if you are just memorizing. You may be tempted to mark covalent bonds or intermolecular forces because they aren't specifically on the "list" most people memorize. However, disulfide bonds are an example of covalent bonds and hydrophobic interactions are an example of intermolecular repulsions. C, alpha helices, is responsible for secondary structure
Which of the following statements is/are true concerning carbohydrates?

I. They contain an equal number of carbons and exgens

II. They can contain aldehyde, ketone and hydroxyl functional groups

III. They are a more efficient long-term energy storage source than are proteins or fats

IV. Both plants and animals utiize them for long-term energy storage
I and II only.

Item III is false because fats are far more efficient that either carbohydrates or proteins. Finally, Item IV is false because plants do use carbohydrates (in the form of starch) as their long-term energy storage device, but animals use fat instead. Animals do, however, use carbohydrates (in the form of glycogen) for short-term energy storage.
All of the following are biomolecules are nucleotides Except:

A. cAMP
B. NADH
C. UTP
D. Adenine
D; A nucleotide is any molecule that contains a sugar backbone, a nitrogenous base and a phosphate group. Cyclic AMP, ADP, ATP, GTP, GMP GDP, NADH, FADH2 and the DNA and RNA subunits are all examples. UTP may look unfamiliar, but it is the equivalent of ATP with a Uracil base instead of an Adenine base. The bases, A, C, T and G, by themselves, ARE NOT nucleotides.
Which of the followning enzymes most likely requires ATP to function properly?

A. Alcohol deydrogenase
B. ATP synthase
C. Glucose-6-phospatae
D. Oxaloacetic decarboxylase
C; If you paid attention during week one, you should get this. The ending -ase tells you it's an enzyme. The ending -tase tells you it is an ATP-requiring enzyme.
Which of the following molecules is not in its biologically reduced state?

A. NADH
B. FADH
C. Pyruvate
D. Glucose
B; You should be familiar with NADH and FADH2 and know that these are the reduced states, while NAD+ and FADH are the oxidized states. Pyruvate is reduced because it is next oxidized by the PDH complex. Glucose is reduced because it has no pre-cursor that is more oxidized and is fully saturated with all of its possible hydrogens. FADH is the oxidized form and is thus the correct answer.
Cancerous cells lose the ability to regulate their won cell division and devide rapidly and indefinitely, causing numerous whole-body diseases and conditions. IF a mass of cancer cells were assayed, all of the following would be found in higher-than-normal concentrations EXCEPT:

A. Mitochondria
B. Microtubules
C. Chromosomes
D. Lysosomes.
C; In rapidly dividing cells we would expect to find all organelles in a larger than normal concentration because many of the cells would have synthesized approximately double their normal amount of organelles prior to cell division. Thus answer choices A and D would likely both be found in above-average concentrations. Answer choice B, microtubules would also be expected to be high due to the fact that microtubules are synthesized by the centrioles during division to form the spindle apparatus. Chromosomes, however, are NEVER duplicated in number during cell division. They are "REPLICATED," meaning each single chromosome gains an identical sister chromatid, but only the amount of DNA has increased, the number of chromosomes has not. Before DNA replication each cell will have 46 chromosomes and afterward each cell will still have ONLY 46 chromosomes; thus, C is the best answer.
A sample of saturated fats is labeled with a blue fluorescent dye and a sample of carbohydrates is labeled with a similar green dye. Both are fed to a cultured, isolated liver cell and fluorescent detection readings are taken over the next several hours. Which of the following would be expected?

A. Green fluorescnece in both the cytosol and the mitochondria; blue fluorescence in the cytosol only

B. Green fluorescence in the peroxisomes, the cytosol and the mitochondria; blue fluorescence in the mitochondria only

C. Blue fluorescnence in the peroximoes and the mitochondria; green fluorescence in the mitochondria and the cytosol

D. Blue fluorescence in the peroxisomes and the mitochondria; green fluorescence in the mitochonria only.
C; The ependymal cells, along with all other neural support cells (astrocytes, oligodendrocytes, etc.), are part of the nervous system. However, cells that line any body cavity are also considered epithelial. Blood and cartilage are both examples of connective tissue. "Blood" is not a tissue type, but the name of a specific tissue, making B false and leaving C as the only plausible answer.
A patient comes in to your clinic and is found to have high nitrogen content in his urine. Which of the following is the LEAST plausible explanation?

A. he has an undiagnosed cancer
B. He is catabolizing structural proteins for energy
C. He is diabetic
D. he has been consuming excess amount of nitrogen
A; The MCAT likes to ask this question over and over again. The primary reason nitrogen would be in the urine is because excess proteins are in the urine, perhaps because they are being broken down somewhere in the body. If you have nitrogen in your urine you are likely 1) diabetic (because you cannot get sugar into your cells and thus must break down proteins for energy), 2) starving to death (you cannot get enough food, so you must break down your body's own proteins), 3) are experiencing severe damage to organs, cell lysis, etc., or 4) are on an Atkins diet, eating more protein than your body can process. All of the answers except A fit this concept.
Substance A is necessary to from substance B. Substance B phophorylates substance C. Substance C releases energy as it is transformed into substance D. Substance D is phosphoantigenitase, a molecule necessary for proper immune function.

It can be inferred that which of the aforementaion substance most likely requires ATP to accomplish its described role?

A. Substance B only
B. Substance A only
C. Substance B and C
D. Substance B and D
D; Answer choice A is possibly correct because we are told that substance B phosphorylates substance C. In human metabolism, substances are almost always phosphorylated using ATP or a similar high-energy phosphate molecule. ATP transfers one of its phosphates to substance B, creating substance C, which would be an example of SUBSTRATE-LEVEL PHOSPHORYLATION. Substance C releases energy as it forms substance D, indicating it probably loses its phosphate to reform ATP; thus it creates ATP and does not require it as asked for in the question. Substance D is an enzyme, and because of the "-tase" ending, we know it requires ATP for its action. Thus D is the best answer.
Protein X is responsible for a dramitc increase in the concentration of sodium ions found in the cytosol of normally functioning cells. Protein X is most likely which of the following?
B; Answer choice A is unlikely because a surface protein does not span the membrane and is unlikely to play a role in Na+ entering the cell. Answer C is impossible because the Na+/K+ pump moves sodium OUT of the cell, not into the cell. Although protein X could be an enzyme involved in a cascade leading to intake of Na+, it would likely require many other players, making this answer less desirable. If the protein were an integral membrane protein, as mentioned in B, this would make the most sense. The protein is likely a transport protein for Na+ ions.
Which of the following statements is/are true regarding human chromosomes?
Statement I is true, chromosomes contain many histones, which are a type of protein. Statement II is false; during most of the cell cycle the chromosomes are unwound. Not until prophase do the chromosomes condense. Statement III is also true; a nucleosome is a set of four histones wound together. Finally, statement IV is true. You may be tempted here to think that we only have 23 pairs of non-identical chromosomes because of the existence of homologues. That would be true IF homologues were identical. However, homologues are definitely non-identical because they contain a random assortment of alleles. Thus, D is the correct answer.
Which of the following statements is/are true regarding chromosomes and DNA?

I. Prior to mitosis, chromosomal DNA doubles in mass

II. During meiosis, the total mass of DNA per cell is reduced by a factor of 4 from prophase I to the end of Telophase II

III. The number of chromosomes remains 46 through all the stages of mitosis
All three are true
All of the following statements regarding the bi-layer phospholipid membrane are false, EXCEPT:

A. Phospholipids, which contain phosphodiester bonds, are the major component

B. Hormones manufactured in the cell cross the membrane via receptor-mediated endocytosis

C. The process by which the membrane envelops extracellular fluids does not require a membrane receptor

D. Cholesterol adds fluidity to the membrane and aids in ion transport
C; Be careful with these double negative type questions. As always, read each choice carefully, ONE-BY-ONE and DON'T jump to an answer. Answer A is false (and thus NOT the correct answer) because phospholipids only have a phosphoester bond, not a phosphodiester bond (as is found in DNA). B is false because hormones exported from the cell would leave via exocytosis, not endocytosis. Finally, D is false because although cholesterol does add to fluidity, it does NOT have any role in ion transport. Thus, C is the best answer. The process referred to in C is "pinocytosis" and it is random and does not require a receptor.
Uptake of glucose from the gut and transport of K⁺ ions thru the voltage-gated channels of a neuron are best described as:

A. Secondary active transport and active transport, respectively

B. Active transport and facilitated diffusion, respectively

C. Secondary active transport and facilitated diffusion, respectively

D. Active transport and diffusion, respectively.
C; Uptake of glucose at both the gut and the kidney is accomplished via a secondary active transport system, meaning that a "secondary" molecule is actually the one actively transported to get the molecule of interest into or out of the cell. In this case, sodium is transported against its gradient, where it pairs with glucose and brings it back into the cell back down sodium's gradient. The flow of K+ ions thru a potassium channel in the neuron does not involve ATP and is thus regular diffusion. However, because it goes thru a channel protein, it is considered "facilitated diffusion" and thus C is the best answer.
Which of the following is NOT a function of the endoplasmic reticulum?

A. detoxification of cellular chemicals
B. lipid production and metabolism
C. Synthesis site of extracellualar protens
D. Post-translational modification of proteins
B; The ER, between the smooth and rough sections, is responsible for detoxifying chemicals, producing lipids, synthesizing extracellular proteins, modifying translated proteins, and various other functions. The key here is that lipids are MADE at the smooth ER, but are metabolized in the mitochondrial matrix. Thus B is a false statement and is the correct answer.
Which of the following gives and accurate ordered list of cellular structures/locations for the production and excretion of an extracellular protein?

A. nucleus, ribosome, golgi, secretory vesicle
B. nucleus, somoth ER, rought ER, golgi, lysosome, secretory vesicle
C. nucleus, rough ER, golgi, secretory vesicle
D. nucleus, free-floating ribosome, smooth ER, golgi, secretory vesicle
C; Answer choice A may be correct, but it is unclear if the ribosome mentioned is on the rough ER or if it is a free-floating ribosome. B is incorrect because proteins bound for excretion out of the cell don't go to the smooth ER and then the rough ER and do not ever go to lysosomes. D is incorrect because it contains "smooth ER." C is the best answer, and is better than A because it specifies that the ribosome is on the rough ER.
The amino acid deleted in the defective CFTR gene, phenylalanine, is shown below (the carboxilic acid is protenated and the amine is nutrutal as well [NH₂]). The pKa of the amine and carboxyl hydrogens are 9.2 and 2.6 respectively. The structure of phenylalanine as shown would predominate at a pH of:

A. 1.5
B. 2.9
C. 10.0
D. Phenylalanine will not exist in physiological conditions as shown
D; This is a good question to test how independent and confident you are in your thinking-which you must be for the MCAT. Most students have a hard time picking D, although it is the correct answer. The amine group on any amino acid has the highest pKa, meaning that it will remain in the NH3+ form until the pH is increased to a very high number, 9 in this case. The carboxyl group has a low pH, usually around 2. This means it will be deprotonated as soon as the pH rises above its pKa (approximately). As shown, Phe has an amine group in the form NH2. This would occur only at a very high pH. At any high pH the carboxyl group would have long ago been deprotonated, yet it is shown here in its protonated form. This is an implausible structure and D is the correct answer.
Kinetics vs Thermodynamics
Thermodynamics tells if if a reaction will go
Kinetics tells us how fast it will go

Thermodynamics is not about things moving and changing but instead about how stable they are in one state versus another, while kinetics is about how quickly or slowly species react.
What is Rate measured in?
Change in Molarity of the reactants per second (M/s)
What causes reactions?
COLLISIONS CAUSE REACTIONS

1)reactants must collide with enough energy to overcome the Energy of Activation
2)The reactants must be in the correct spatial arrangement
Overall Order of a reaction is...
The some of the exponents in the rate law
How to you find the "order" of each reactant
To calculate the "order" of each reactant using experimental data:

1) Find two trials where the [reactant] in question changed, but ALL OTHER PARAMETERS DID NOT (i.e., concentration of other reactants, temperature, etc.)
2) Note the factor by which the reactant concentration changed
3) Note the factor by which the rate changed across those same two trials
4) Use the following equation: XY = Z ; where X = the factor by which the [reactant] changed, Z = the factor by which the rate changed, and Y = the order of the reactant.
Rate Order Graphs:
These graphs will only be linear when the reactant graphed is from a single reactant reaction OR when it is part of a multiple reactant reaction where ALL other reactants are NOT in the rate law (i.e., zero order).

Zero Order: [A] vs. time is linear (i.e., yields a straight line) with slope = -k

First Order: ln[A] vs. time is linear with slope =-k

Second Order: 1/[A] vs. time is linear with slope = k

Third Order: ½[A]2 vs. time is linear with slope = k
Rates of Multi-Step Reactions:
The slow step ALWAYS determines the rate.

If slow step is first, the rate law is written as if it were the only step.

If the slow step is second (based on some assumptions) the rate law is the rate law of the slow step with the intermediate added.
Catalysts
any substance that increases reaction rate without itself being consumed in the process
Homogeneous catalysts
Homogeneous catalysts function in the same phase as the reactants. Typically homogeneous catalysts are dissolved in a solvent with the substrates.
Heterogeneous catalysts
Heterogeneous catalysts act in a different phase than the reactants. Most heterogeneous catalysts are solids that act on substrates in a liquid or gaseous reaction mixture
A student submits the following partial data table for a lab project in which students analyzed the reaction of nitric oxide with hydrogen gas. It is known that the reaction is second order with respect to nitric oxide.

2 NO(g) + 2 H2(g) N2(g) + 2 H2O(g)

Trial [NO] [H2] (mol/L*s)
1 0.004 0.004 1.25 x 10-2
2 0.002 0.004 7.8 x 10-4
3 0.001 0.001 1.95 x 10-4
4 0.008 0.016 ?

1) The order of the above reaction with respect to hydrogen gas is:

A) zero order
B) first order
C) second order
D) cannot be determined without additional information
Solution: There are no trials across which [H2] changes, while [NO] remains constant. Normally, this is what we look for first to predict rate order. However, we were given the information that it is 2nd order with respect to NO. If we divide the rate for Trial 1 by the rate for Trial 3 we see that the rate decreased by a factor of 64. Knowing the order of NO, we can say that when [NO] went down by a factor of 4, the rate should have gone down by a factor of 16. It actually went down by a factor of 64, or 16*4. Thus the effect of the change in the [H2] must have accounted for this additional 4-fold decrease. Using x = yz we can see that if concentration went down by 4 and rate also went down by 4, the reaction must be first order with respect to H2. It will help to recall form the manipulating equations section that if two variables are changed by factors x and y, respectively, the overall change to the equation is equal to x times y. B is the correct answer.
The lab instructor asks the student to estimate the expected rate for Trial 4. Compared to the rate of Trial 3, Trial 4 should be approximately:

Rate=k [NO]²[H2]

Trial [NO] [H2] (mol/L*s)
3 0.001 0.001 1.95 x 10-4
4 0.008 0.016 ?

A) 64 times faster
B) 128 times faster
C) 256 times faster
D) 1024 times faster
1024 times faster
Three kinds of Heat Exchange:
1) Convection: fluid movement caused by the hotter portions of a fluid rising and the cooler portions of a fluid sinking.

2) Radiation: electromagnetic waves emitted from a hot body into the surrounding environment.
Light colors radiate and absorb less
Dark colors radiate and absorb more
Black Body Radiator = perfect theoretical radiator

3) Conduction: molecular collisions along a conduit
Heat conduction is approximately equivalent to current flow thru a wire or water flow thru a pipe.
Heat Capacity
the measurable physical quantity that characterizes the amount of heat required to change a substance's temperature by a given amount. In the International System of Units (SI), heat capacity is expressed in units of joule(s) (J) per kelvin (K).

C = q/∆T

C=the heat capacity
q=heat flow in
T=change in temp of object
Specific Heat Capacity (Specific Heat)
we defined Heat Capacity as energy/change in temperature of a system. This could be a single substance or a complex system such as a liquid, the container and a thermometer. Specific Heat Capacity, however, is for a given substance only and is thought of as the heat capacity per unit mass. Little "c" is used instead of big "C".

Formula:
c = q/m∆T ; often re-written as: q = mc∆T
Specific Heat of water = 1.0 cal/g˚C or 4.18 J/g˚C
What is the Specific Heat of Water
Specific Heat of water = 1.0 cal/g˚C or 4.18 J/g˚C
Beaker A contains 2.55 g of FeCl3 dissolved in 100mL of water. Beaker B contains 10.20 g of FeCl3 dissolved in 400mL of water. If the specific heat capacity of the solution in Beaker A is known to be 1.33 cal/g˚C, what is the expected specific heat capacity of the solution in Beaker B?

A) 1.33 cal/g
B) 2.66 cal/g˚C
C) 5.32 cal/g˚C
D) Solutions do not have specific heat capacities
The two solutions have the same molar concentration of FeCl3, Beaker B simply contains four times as much of it. Specific Heat Capacity is an intensive property and thus should not vary with amount. This makes A the best answer. Note, however, that had the question asked for Heat Capacity—which refers to the heat absorption of the system as a whole instead of per gram or per mole—then Beaker B would indeed have approximately four times the Heat Capacity.
What is the purpose of a calorimeter?
Used to calculate enthaly (∆H).

We are assuming that q (which is what the calorimeter actually measures) is equal to ∆H.

This is true at constant pressure
Coffee Cup Calorimeter
Solve using:

q=mc(deltaT)
Bomb Calorimeter
Solve using: q = C∆T.

This does NOT give enthalpy, but change in internal energy, usually called ∆U or ∆E. Use heat capacity (big C) instead of specific heat capacity (little c).
Pressure-Volume (PV) work
PV work=P(∆V)

Requires constant pressure, ANY change in volume tells you there is PV work

On a PRessure vs Volume graph, the area under the curve is the PV work
Which of the Calorimeters allows for PV work?
Coffee cup calorimeter
Which Calorimeter proceeds at constant pressure?
Coffee cup calorimeter
Which Calorimeter proceeds at constant volume?
Bomb Calorimeter
The First Law of Thermodynamics
delta E= q +w

In chemistry, by convention, the work done ON a system is positive, work done BY the system is negative. (like Endothermic is Positive Exothermic is Negative)
The Second Law of Thermodynamics
Heat cannot be changed completely into work in a cyclic process; And entropy in an isolated system can never decrease

Basically, perpetual motion is impossible
The Third Law of Thermodynamics
Pure substances at absolute zero have an entropy of zero
The Zeroth Law of Thermodynamics
Temperature exists

KE= 3/2kT (where k is the boltzman's constant)
0°C = what in Keliv
273.16 K
what gas has the greatest velocity and kinetic energy if the temp is 314 K?

CO
CO₂
SO₃
All molecules have the same KE
and the smallest molecule has the greatest velocity
Enthalpy (∆H)
THINK OF ENTHALPY AS: Enthalpy = the energy contained within the bonds.

Units: Joules

Standard State: a complicated set of circumstances chosen as the reference point for measuring enthalpy, entropy and Gibbs Energy.

DON'T confuse with STP.

Elements in their standard state have delta H° = zero. This is because elements in their standard state are not formed, or created and thus there is no change in bond energy or associated flow of energy. The enthalpy change for graphite, for example, is zero. However, the enthalpy change for diamond is 2 kJ/mol because there is energy required to form diamond out of graphite.
Enthalpy of Reaction (∆H_reaction)
Calculated most often by adding half-reactions from a table. If the half-reaction proceeds in the same direction, use the number directly. If it proceeds in the opposite direction, change the sign. Remember to multiply the number given in the table by the coefficient in the balanced equation. It can also be calculated by adding the bond energies. If the bond is formed, the bond energy is negative; if it is broken, the bond energy is positive.
Enthalply of Formation (∆H_formation)
The enthalpy value for the formation of a compound from its elements in their standard states. If the number is negative, formation is an exothermic process, if it is positive, the process is endothermic.
Enthalpy of combustion (∆H_combustion)
The enthalpy value for the combustion of a compound with O2 to form CO2 and water. A HIGH heat of combustion is associated with an unstable molecule and a LOW heat of combustion with a stable molecule.
Enthalpy of solution (∆H_solution)
The enthalpy value associated with a species dissolving into solution. We'll discuss this in more detail when we cover solution chemistry.
Enthalpy of Vaporization (∆H_vaporization)
The enthalpy value associated with a species dissolving into solution. We'll discuss this in more detail when we cover solution chemistry.
Enthalpy of fusion (∆H_fussion)
The enthalpy value associated with the phase change from solid to liquid OR from liquid to solid.
Entropy (∆S)
Definition: THINK OF ENTROPY AS: Entropy = a measure of the randomness or disorder in a system.

Units: Joules/K

As a reaction proceeds, if randomness increases, energy will be released and thus be available to do work. If randomness decreases, energy is required to "create" this increased order and that amount of energy will thus be unavailable to do work.

+ ∆S = increased randomness, and thus MORE energy available to do work.
- ∆S = decreased randomness, and thus LESS energy available to do work.

Reactions at equilibrium are at maximum entropy.
Entropy Increases with:
1) increased number of items/particles/etc. (caveat: the number of moles of gas TRUMPS the number of moles, or particles. Thus, even if 2 moles of reactants turns into 1 mole of product, if that one mole of product is a gas and the reactants are not, entropy has increased and ΔS is positive)
2) increased volume
3) increased temperature
4) increased disorder
5) decreased pressure (increased pressure increases order by packing the same molecules into a smaller space, thus decreasing entropy)
Gibbs Free Energy (∆G)
THINK OF GIBB'S FREE ENERGY AS: ∆G = the amount of "free" or "useful" energy available to do work (excluding pv work; as a result of running an isothermal, isobaric reaction).

If energy is available, Gibb's Free Energy is said to be negative. If energy must be added to the reaction (i.e., work must be done on the system) to make it proceed, Gibb's Free Energy is said to be positive

Units: Joules

- ∆G = SPONTANEOUS, free energy available to do work.
+ ∆G = NON-SPONTANEOUS, no free energy available, energy must be added.
Isothermal
Temperature is constant (heat can flow in or out)

An isothermal process is a change of a system, in which the temperature remains constant: ΔT = 0. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change occurs slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange. In contrast, an adiabatic process is where a system exchanges no heat with its surroundings (Q = 0). In other words, in an isothermal process, the value ΔT = 0 but Q ≠ 0, while in an adiabatic process, ΔT ≠ 0 but Q = 0.
Isobaric
pressure is constant

An isobaric process is a thermodynamic process in which the pressure stays constant. The term derives from the Greek isos, (equal), and barus, (heavy). The heat transferred to the system does work but also changes the internal energy of the system:


The yellow area represents the work done
The Fundamental Thermodynamic Relation
∆G = ∆H - T∆S

Recall that enthalpy is basically the change in bond energy from reactants to products. If there were no change in randomness during the reaction, the amount of energy available to do work (ΔG) would be exactly equal to enthalpy. As described above, if randomness increases (+ΔS), energy will be released and that energy (in addition to ΔH) will also be available to do work (creating a larger, more negative ΔG). By contrast, if randomness decreases, energy will be "used" to create this order, decreasing the amount of energy available to do work. The "T" term in the equation simply converts entropy into joules (J/K*K = J). You may recall that energy can also be used to increase temperature OR to expand the volume (pv work), but neither occurs here because the system is both isothermal and isobaric.
If ∆H is positive and entropy is negative, what will ∆G be?
Positive
If entropy is positive and enthalpy is negative, the reaction is:

a) spontaneous
b) non-spontaneous
c) can be either spontaneous or non-spontaneous depending on temperature.
Spontaneous
The hydration of ammonium nitrate is a highly exothermic dissolution reaction. Which of the following statements is NOT true of this process?

A) The reaction must be spontaneous because it is both exothermic and has a favorable entropy change.
B) The reaction could be spontaneous or non-spontaneous depending on the temperature at which the reaction is run.
C) The products of the reaction have greater entropy than do the reactants.
D) The total bond energy of all the products exceeds the total bond energy of all the reactants.
Answer A states in words what is demonstrated by the fundamental thermodynamic relationship: ∆G = ∆H - T∆S. Namely, if both the enthalpy term and the T∆S term are negative, the reaction must be spontaneous. Answer C states the conditions for having a positive entropy change, which we know this reaction does have because it is a dissolution reaction. Answer D states the conditions for being exothermic, which this reaction is, as given in the stem. Answer B WOULD be true if the signs of enthalpy change and entropy change were both negative, or both positive, but they are not in this case. We are looking for a statement that is NOT true, so B is the correct answer.
How will increasing [products] affect the rate of reaction?
it will go down
What does a higher heat capacity mean?
it can absorb more energy per unit temperature
(its harder to heat up)
For the same substance, which heat capacity will be greater, the constant volume or the constant pressure?
Constant pressure (because more energy will be needed to increase the temp of the substance if it can expand)
For a reaction with two reactants, A and B, a graph of 1/[A] vs. time is non-linear. Which of the following is known?

1)Reactant A cannot be second order
2)Reactant B must be involved in the rate law
3)Reactant B cannot be in excess
Reactant A cannot be second order
For a reaction with two reactants, A and B, a graph of ln[A] vs. time is linear. Which of the following is known?

1)Reactant A must be first order
2)Reactant B could be first order
3)Reactant B cannot be involved in the rate law
4)Reactant B must be in excess
Reactant A must be first order

Reactant B could be first order
Which of the following represent an example of heat conduction and heat radiation, respectively?

I. Air flow within a convection oven and heat created by a household radiator
II. A chicken sitting on her eggs to keep them warm and heat escaping from the skin after exercise
III. A heating blanket wrapped around a victim just rescued from a blizzard and heat escaping from a non-insulated, current carrying wire

A. I only
B. II only
C. II & III
D. I, II & III
C; Statement I does not qualify because air flow in a convection oven is a clear example of convection, as the name implies. When you think of convection, think of hot and cold air naturally flowing and creating currents in a fluid—such as air or ocean currents. Statements II and III Both describe an example of conduction first—which is natural flow from hot to cold due to two things being in contact—and then radiation—which is the flow of energy from an object that is hotter than its environment into the environment via electromagnetic radiation.
A student examines the heat of formation of MgCl2(s) using both a bomb calorimeter and a coffee-cup calorimeter. The student's results from the bomb calorimeter give a higher ∆Hrxn than his results from the coffee cup calorimeter. Which of the following provides the best explanation?

A. Coffee cup calorimeters are less accurate than bomb calorimeters
B. Bomb calorimeters are less accurate than coffee cup calorimeters
C. Both are equally accurate, but coffee cup calorimeters allow for pv work, while bomb calorimeters do not.
D. Both are equally accurate, but the reaction mixture increases in volume in a bomb calorimeter, but does not in a coffee cup calorimeter
C; Answers A and B are false because neither calorimeter is known to be particularly more accurate; they merely serve different purposes. Answer D is false because volume changes in the coffee-cup calorimeter, NOT in the bomb calorimeter. Answer C is correct because the change in volume that occurs in a coffee-cup calorimeter means that some of the energy input from the reaction went to PV work instead of raising the temperature of the vessel. This would give a lower value for the heat of reaction in the coffee cup calorimeter as compared to the bomb calorimeter where no PV work can be done.
Which of the following gives the enthalpy of reaction (∆Hrxn), for the reaction shown below:

H2(g) + F2(g) 2HF(ℓ)

BOND ENERGIES
Species Bond Energy (kJ/mol)
H2(g) 400
F2(g) 150
HF(g) 600

A. +650kJ/mol
B. +1750kJ/mol
C. -50kJ/mol
D. -650kJ/mol
Always pay attention to moles and multiply whatever number you use by the number of moles of the species involved in the overall reaction. In this case, you are breaking apart hydrogen and fluorine gases, so use the positive value for their bond energies; and you are forming 2 moles of HF, so use the value given in the heats of formation table for HF, but double it. Add these all together and you should get -650kJ/mol.
A 0.001kg mass increases in temperature from 250K to 275K when 1000J of heat is applied. Which of the following gives the specific heat capacity?

A. 4 x 104 J/kg*K
B. 40 J/kg*K
C. 250 J/kg*K
D. 1000 J/kg*K
A; In case the units aren't given, it is good to know that specific heat is measured in either J/kg*K or in cal/g*˚C. However, since you know the units here from the answer choices, this should be easy. Just solve q = mc∆T for c and fill in the info given. You should get c = q/m∆T. Plugging and chugging we get: 1x103J/(25K*1x10-3kg), which equals 4 x 104, or answer A.
For a reaction in which A and B combine to form C, and B is known to be in excess, a non-linear plot of ln[A}versus time indicates which of the following?

A. the reaction is first order
B. the reaction may be first order
C. the reaction is not first order with respect to A, but may be first order with respect to B
D. the reaction is not first order
D; Recall that these rate order graphs ONLY work under one of two conditions ("work" meaning any of them will give you a linear line): 1) the reaction has only one reactant, or 2) there are two or more reactants but only ONE of them is in the rate law. So, a non-linear graph means that either the reaction does have only one species in the rate law but it is NOT the order with respect to that species associated with that graph, or it could mean that both A and B are in the rate law—in which case none of the graphs would give a linear line. These facts, applied to this problem, show that Answer A is clearly false. Under any circumstance, if the reaction were first order this graph would give a linear line, BECAUSE B is in excess and it therefore must be zero order. However, a graph of 1/[A] could also give a linear line if the reaction is second order with respect to A. Answer B is false for the same reason; this is NOT first order. Answer C is false because B is in excess. Answer D is all that we really know for sure.
If a reaction is spontaneous, what can we infer about the rate of that reaction
Gibb's free energy is negative, we also know that K must be greater than one from the equation: ∆G = -RTlnK
If the value of K(eq) is known, what can we infer about ∆G?
...
What is an equation that relates ∆G and K
∆G = -RTlnK(eq)

or

K(eq)=e^(-∆G/RT)
A student is using a coffee cup calorimeter to determine the enthalpy of a reaction. When assembling the apparatus, one of the coffee cups is accidentally torn along one side. The student checks to make sure the reactants aren't leaking out and decides to continue with the experiment. The value he calculates for the heat of reaction:

A. will be higher than the true value
B. will be lower than the true value
C. will be unaffected because he is using two coffee cups
D. minus the heat that escapes thru the crack, will equal the true value
B; The crack would reduce the insulating efficiency of the calorimeter and we would assume that some heat would be lost. The student will measure the change in temperature and use that value to calculate the energy released by the reaction. However, the reaction will have actually produced MORE heat that the heat required to raise the temperature by the amount shown because some of the heat escaped. Thus, his value will be lower than the actual value, Answer B. Answer D is false because the heat escaped would have to be added to this value to get the true value, not subtracted.
Bohr Model
electrons travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction

The model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen

the Bohr model is still commonly taught to introduce students to quantum mechanics, before moving on to the more accurate but more complex valence shell atom
alkali metals
Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium
alkaline earth metals
metallic elements in group 2 of the periodic table which are harder than the alkali metals and are also less reactive
lanthanides
the first of the two rows below the main part of periodic table. usually used in alloys, soft, malleable, shiny and good electrical conductors
actinides
in the 2nd row of transition metals, radioactive, unstable, do not occur in nature
Electron Affinity
the amount of energy released when an electron is added to a neutral atom or molecule to form a negative ion.
X + e− → X−

It increases from left to right and from bottom to top
Electronegativity
The ability of an atom to attract electrons when the atom is in a compound

It increases from left to right and from bottom to top
Ionization Energy
the energy required to remove 1 mole of electrons from 1 mole of gaseous atoms or ions. Large atoms or molecules have a low ionization energy, while small molecules tend to have higher ionization energies.

It increases from left to right and from bottom to top
Atomic Radius Trends
Atomic radius gets smaller from left to right and bottom to top
Metallic Character Trends
Increases form left to right and bottom to top
First Quantum Number
"n" (the principle quantum number)

ives the Shell (i.e., Valende electrons are in the outermost "shell") and is approximately equal to the relative energy of electrons in that shell
Second Quantum Number
"l" (the azimuthal quantum number)

Gives the subshell: has values of 0,1,2,3 and from this were know the shape:

0=S ; 1=P ; 2=d ; 3=f
Third Quantum Number
"m(subL)" (the magnetic quantum number)

"the magnetic quantum number"
Gives the orbital; has a value of -l to l (from the azimuthal quantum number)

The orbital is the portion of the subshell where an electron is most likely to be found (i.e., which "dumbbell" of a p subshell)
Fourth Quantum Number
"m(subS)" (the electron spin quantum number)

Gives the spin which is either +1/2 or -1/2 (up arrow or down arrow)
Heisenberg uncertainty principle
states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known. In layman's terms, the more precisely one property is measured, the less precisely the other can be controlled, determined, or known.

(you can know how fast it is going, or where its at, but you can't know both at the same time)
Pauli exclusion principle
no two electrons in a single atom can have the same four quantum numbers; if n, l, and ml are the same, ms must be different such that the electrons have opposite spins, and so on.
what is The Work Function
If you bombard certain metals with energy, you can cause the ejection of an electron from their outermost shell (i.e., valence electron). The amount of energy required to do this is called the "work functions."

This is not the same as the Ionization energy because that refers to only lone atoms in a gaseous state. The work function refers to the valence electrons being ejected from the surface of a metal
Formulas for the Work Function
KE=E-(funky P)

E= the amount of energy added, KE is the kinetic energy of the ejected electron and the (funky P) is the "work function" (the amount of energy needed to eject an electron).

Because energy is often added via bombardment with photons, E can be replaced with hf, the formula for the nervy of a photon; where h=plank's Constant and f=frequency
What is a formula that would allow you to calculate the energy of a photon knowing only velocity and wavelength?
E=hv/(landa)
Beta Decay
A neutron is changed into a proton with the ejection of an electron
Electron Capture
A proton is changed into a neutron via capture of an electron
Alpha Decay
The loss of one He nucleus, which has a mass of 4 and an atomic number of 2
A substance decayed from 500g to 31.25g in a space of 40 years. What is the half life of the substance?
10 years
Two unique light sources are used to bombard a single metal sample with potions (funky p=349J). The fist light source delivers photons with an energy of 700J at a rate of 1x10^5 photons per second. The second light source delivers 350 J photons at exactly twice that rate. If each light source is shown onto the surface of the metal for exactly one second, which of the following statements is true?

a) The second light source will eject twice as many electrons as the first
b)The second light sour will eject half as many electrons as the first.
c)Neither light source will eject elections.
d)Electrons ejected byt eh second source will have grater kinetic energy.
Answer A is correct. because both light sources deliver photons with energies that exceed the work function, both will eject electrons in a one-to-one ration with photons.
Good vs Poor Electrolytes
Covalent compounds that dissociate 100% in water, such as strong acids and strong bases, make good electrolytes. Other covalent compounds are usually poor electrolytes.

IONIC COMPOUNDS ALWYAS MAKE GOOD ELCECTROLYTES
Ionic Character
All bonds have some ionic character. It is basically a measure of the polarity of the bond

NaCl would have near 100% ionic character
Condosity
The condosity of a solution is defined as the molar concentration of sodium chloride that has the same specific electrical conductance as the solution.

For example, for a 2M KCl solution, we would expect the condosity to be something more than 2. Because potassium is more metallic than sodium. Thus, we know that it will be a better conducted. This means the NaCl solution will have to be slightly more concentrated to conduct as well as the KCl solution
What is the expected condosity of a 3M LiCl solution?
less than 3
Heat of Combustion
The amount of energy released when a molecule is combusted with oxygen. All covalent bonds are broken and refored in a radical reaction.

THE HIGHER THE ENERGY OF THE MOLECULE (I.E., LESS STABLE0 THE HIGHER THE HEAT OF COMBUSTION.
What has a higher bond energy, N₂ or ATP?
Stable compounds such as N₂ have higher bond energy (the energy stored in the bond) than unstable compounds such as ATP.
Empirical vs Molecular formulas
The empirical formula is the simplest formula for a compound. A molecular formula is the same as or a multiple of the empirical formula, and is based on the actual number of atoms of each type in the compound. For example, if the empirical formula of a compound is C3H8 , its molecular formula may be C3H8 , C6H16 , etc.
What is the percent mass of carbon in glucose?
40%
What is the percent mass of hydrogen in water
11%
What are the steps to derive a empirical/molecular formula from Percent Mass
1) Change the percent for each species into moles by deciding by molar mass.
2) Convert the grams of each species into moles by dividing by molar mass.
3) Look at the element with the lowest number of moles. Calculate approximately how many times it will divide into each of the other molar amounts for each of the other elements -- this number is the subscript for each element in the empirical formula. If the subscripts are not at there lowest common denominator, reduce to get the empirical formula.

AN EMPIRICAL FORMULA IS ALL YOU CAN GET FORM PERCENT MASS ALONE. TO GET THE MOLECULAR FORMULA, YOU MUST BE GIVEN THE MW O THE UNKOWN COMPOUND. Then simply divide that MW by the MW of the empirical formula. You should get a whole number. Multiply each subscript by that number to get the molecular formula.
How to name general Ionic compounds
Name the cation first, then the anion (e.g., CaSo₄ is Calcium Sulfate)
How to name Transition Metals
When written in words, compounds including transition elements must have a roman numeral showing the oxidation state of the metal (i.e., Iron(II)Sulfate vs. Iron(III)sulfate).
How to name Monatomic ions
Named by replacing the last syllable with "die" (i.e., Sulfide, Hydride, Chloride, etc.)
NO₃⁻
Nitrate
NO₂⁻
Nitrite
ClO₃⁻
Chlorate
ClO₂⁻
Chlorite
ClO⁻
Hypochlorite
ClO₄⁻
Perchlorate
CO₃²⁻
Carbonate
HCO₃⁻
Bicarbonate
NH₃
Ammonia
NH₄⁺
Ammonium
SO₄²⁻
Sulfate
PO₄³-
Phosphate
MnO₄²⁻
Manganate
CN⁻
Cyanide
How to name Acids
"ate" becomes "ic" (Sulfuric/Nitric acid)
"ite" becomes "ous" (Nitrous acid)
"ide" becomes "hydro/ic" (hydroiodic/hydroflouric acid)
Naming Binary Compounds
Name the element furthest down and left on the periodic table first

use poly prefixes as necessary (i.e., Nitrogen Trioxide, Carbon Monoxide, Sulfure Dioxide, etc.)
Combination
two or more reactants are chemically bonded together to produce a single product
Decompostion
the separation of a chemical compound into elements or simpler compounds
Single Displacement
also called single-replacement reaction, is a type of oxidation-reduction chemical reaction when an element or ion moves out of one compound and into another. (One element is replaced by another in a compound.) This is usually written as...
A + BC → AC + B
Double Displacement (a.k.a. "metathesis reaction")
Involves two replacements

AgNO₃ + HCl AgCl + HNO₃
write the balanced reaction for the combustion of methane
4H₃C + 7O₂ → 4CO₂ + 6H₂O
write the balanced reaction for the combustion of ethane
2C₃H + 7O₂ → 4CO₂ + 6H₂O
write the balanced reaction for the combustion of cyclopentane
2C⁵H₁₀ + 15O₂ → 10CO₂ + 10H₂O
Steps in balancing reactions
1) Balance Carbons
2)Balance Hydrogens
3)Balance oxygens
4) Balance others

(if necessary, use fractions to balance; i.e., if you have seven oxygens on one side and O₂ on the other, put 7/2 in front of the O₂)

5)finally, multiply all species by the number in the denominator of any fraction to remove the fractions

YOU MUST DOUBLE-CHECK EVERY REACTION YOU SEE ON THE MCAT TO MAKE SURE IT IS BALANCED. YES, THEY WILL GIVE YOU UNBALANCED REACTIONS WITHOUT TELLING YOUR!
Avogadro's number
6.022x10²³
How to find limiting reagent
1) Convert to moles
2) Balance the equations
3) compare the number of moles you have to the number of moles required
Percent Yield
Reactions rarely produce the predicted amount of product from the masses of reactants in the reaction .An example of this is the reaction of carbon with oxygen. Normally we expect a 1 mol yield of carbon dioxide for every mol of carbon burned. This does not always happen.

C(s) + O2(g) --- > CO2(g)

If you burn 12 grams of carbon to make CO2, then amount of carbon dioxide expected is one mol of CO2 or 44 grams of CO2.

Sadly the amount you will get will probably be less than 44 grams and more like 34 grams of CO2. The problem is a competing reaction that happens. Some carbon reacts to make CO.

2 C(s) + O2(g) --- > 2 CO(g)

The carbon participating in this "side" reaction will not be able to make CO2. The reaction will not yield 100% of the expected CO2.

The amount of carbon dioxide produced, 34 grams of CO2 is only 77% and not 100 % of the expected 44 grams.

Percent yield = 100 x ( 34 grams CO2 actual / 44 grams CO2 predicted ) = 77 %

The percent yield is defined as
Which takes the most oxygen to combust: Propane, Propanol or Propanoic acid?
Propanoic acid (CH₃CHCOO⁻)

Add 1.0 for each carbon and subtract 0.5 for each oxygen. The species with the lowest total will require the least oxygen and the one with the highest total will require the most.

This is not however, the actual number of moles required. The only way to determine the exact moles of oxygen required is to write out and balance the combustion reaction.
Keq
Keq=[products]^x/[reactants]^y

Keq is written with every term raised to an exponent equal to its coefficient in the balanced equation (remember, however, that you do NOT do this when writing rate laws). Pure liquids (l) and pure solids (s) are never included!
The Reaction Quotient (Q)
The equilibrium constant can ONLY by calculated at equilibrium. IF you make the exact same calculation using concentration values taken at any point other than equilibrium the result is called the REACTION QUOTIENT, Q.

If Q > K, run will proceed to the left
If Q < K, run will proceed to the right
Le Chatelier's Principle
Systems starting at equilibrium the experience change in concentration, temperature, volume, or partial pressure will shift to reduce the effects of that change
How does increasing temperature in an exothermic reaction change Keq
Increases it which shifts the equilibrium to the left making more reactants
How does decreasing pressure change the Keq of the following reaction 2H₂SO₄→ 2H₂O + 2SO₂ + O₂
decreases it which shifts the equilibrium to the right making more products
What electron is higher in energy, 4s or 3d ?
3d
A certain metal is known to have a work function of 500J. If a photon of 500J strikes the surface of the metal, what will be the result?
Nothing, KE=500-500
therefore the ejected electron has no KE and so isn't actually ejected.
How can you increase the yeild of a reaction
1)start with more reactants (this will increase overall quantity of yeild, but not percent yeild)
2)shift the equilibrium to the right using one of th actions described by Le chatelier's priciple
Which of the following is most likely to form a coordination compound with Nickel?

A. CH4
B. BeF3
C. PH3
D. NH4+
Coordination compounds, a.k.a. coordinate covalent bonds, are bonds in which one atom donates BOTH of the electrons necessary to form a sigma bond. This usually occurs between a transition metal with a high positive oxidation state and an atom containing a lone pair. NH3 bonded multiple times to a transition metal is probably the most common one you will see [ i.e., Co(NH3)4]. Answer choices A, B and D do not have lone pairs. Answer choice C does have a lone pair and is very similar to NH3.
Given the following unbalanced reaction, which of the following actions would most likely increase the pressure inside the reaction vessel?

SO3(g) + H2O(g) ↔ HSO4-(aq) + H2(g)

A. Adding more SO3
B. Adding more HSO4-
C. Removing HSO4-
D. Removing H2
B; This is testing LeChatelier's principle. The action that will increase the pressure in a reaction vessel is any disturbance that will push the equilibrium toward the side of the reaction containing more moles of gas. To truly know which side has more moles of gas, you must balance the equation first. This equation is balanced when a 2 is placed in front of the first three species and a one is left in front of the H2. With 4 moles of gas on one side and only one on the other, it is fairly clear that anything pushing the reaction to the left will increase pressure. The only answer choice that would shift the equilibrium left is answer choice B. You may have arrived at the right answer without balancing the equation. If you did, learn your lesson. The balancing could have easily made the right side have more moles of gas. Always balance first!
Consider the following reaction:

SO2(g) + O2(g) ↔ SO3(g) ∆H = -195 kJ/mol

Which of the following would result if the temperature of the reaction vessel is decreased?

A. the reaction would move to the left
B. the reaction would move to the right
C. the reaction would be unchanged
D. the rate of the forward reaction would decrease and the rate of the reverse reaction would increase
B; This is another LeChatelier's principle question. The key is to note that the reaction is exothermic. When you see exothermic (indicated by a -∆H or because they tell you it "evolves heat," raises the temperature of the reaction vessel, or something similar) IMMEDIATELY write out the reaction on your scratch paper and place a ∆ (delta) on the right side of the equation, signifying heat as a product. If it is endothermic put the delta on the left side signifying heat as a reactant. Now treat it like any other reactant or product. Raising the temp is like adding more of it and lowering the temp is like taking some of it out. In this case it would be like taking some of a product out from the right side, so the reaction would shift to the right to compensate. Answer D may be tempting, but decreased temperature slows the rate of both the forward and reverse reactions by decreasing the number of collisions.
Suppose that NASA has landed the space shuttle on a distant, previously undiscovered planet. Researchers discover thru soil samples several new elements not found on earth. Below is a table of properties for these new elements:

Symbol A.Radius Ionization E.

Qr 125.2 30 J
Zi 34.3 240 J
Iv 126.4 101 J
Mx 120.1 44 J
Qa 25.5 345 J


Which of the above elements is likely to exhibit the most metallic character?

A. Qr
B. Iv
C. Qa
D. Mx
A; This is a classic MCAT-style question. You are being tested on your understanding of the properties of the elements and trends in the periodic table, but in an abstract situation you could not have possibly studied before. Just use the principles you know and relax! MCAT almost always has some very easy, reasonable, logical principle behind their questions . . . you can do this! In this case, you are asked about metallic character. Metals behave the way they do for two reasons: 1) they are BIG and 2) they have low ionization energies (i.e., they lose electrons easily). Of the elements listed, the largest is Iv. However, be careful, because it also has a fairly high ionization energy compared with others on the table. Because metals wouldn't conduct electricity, be malleable, form cations, or any of their other characteristic behaviors if they had high ionization energies, Qr is a better answer. It is still large, but also has the lowest ionization energy on the table.
Suppose that NASA has landed the space shuttle on a distant, previously undiscovered planet. Researchers discover thru soil samples several new elements not found on earth. Below is a table of properties for these new elements:

Symbol A.Radius Ionization E.

Qr 125.2 30 J
Zi 34.3 240 J
Iv 126.4 101 J
Mx 120.1 44 J
Qa 25.5 345 J


Which of the above elements is likely to exhibit the most metallic character?

A. Qr
B. Iv
C. Qa
D. Mx
B; The element that will form the most polar acid hydride will be the one that is the most electronegative. Although we don't have electronegativities listed, we can predict them fairly well. Those atoms with the smallest radius and largest ionization energy will be the most electronegative. Qa matches both these criteria and is thus the best answer.
A group of students is studying the compound Fe2(SO4)3 ¬¬ in the lab. Which of the following gives the correct name of this compound along with the oxidation number of sulfur?

A. Iron(II)Sulfate; 3+
B. Iron(II)Sulfate; 2+
C. Iron(III)Sulfate; 6+
D. Iron(III)Sulfate; 8+
C; The correct name is Iron(III)Sulfate. We know this because we know that sulfate ions always have a 2- charge and there are three of them in the molecule, making a total of 6-. Because overall molecule has no net charge, the two Fe atoms present must exactly balance out that 6- charge. This is only possible if they are both 3+. We use similar logic to decide that the oxidation state of sulfur is 6+. Oxygen is normally 2- and there are 4 of them in the sulfate ion for a total of 8-. The overall charge on sulfate is 2-, so this could only be accomplished if sulfur had a 6+ oxidation state.
An unknown compound is analyzed and is found to contain 83% carbon and 17% hydrogen, by mass. What is the compound's empirical formula?

A. C2H5
B. C8H2
C. C6H5
D. C4H10
A; To get an empirical formula, assume a 100 gram sample, meaning we have 83 grams of carbon and 17 grams of hydrogen. Next, change these grams into moles. This gives us exactly 7 moles of carbon and 17 grams of hydrogen. This is where many people get confused. The moles you come up with are NOT the subscripts in the empirical formula, or even in a molecular formula. They just tell us the relative ratio between the different compounds. In this case, we see that there are about 2.5 times more moles of hydrogen than carbon. Answer choices A and D both show this ratio, but A is the correct answer because we are looking for an empirical formula, which is always the lowest possible denominator.
Phosphorous pentafluoride, PF5, can best be described as:

A. a covalent conductor
B. a malleable ionic compound
C. a covalent non-conductor
D. a non-metal ionic compound
C; PF5 is not ionic because it involves two non-metals, indicating that it is covalent. Covalent molecules are not good conductors unless they happen to be good electrolytes. Even then, it is the solution of the ions in water that is a good conductor, not the pure compound itself (HCl is an example). PF5 is not acidic and will not form ions in solution; thus, phosphorous pentafluoride is best described as covalent and a non-conductor. There is no such thing as a non-metal ionic compound.
Which of the following represents an ionic, covalent and coordinate covalent bond, respectively?

A. KCl, HCl and PCl5
B. NH4Cl, NH4+ and Cu(NH3)4
C. NaCl, CH4 and Co(CH4)
D. LiH, PbNO3 and Ni(PBr3)
B; Because we know that compounds involved in coordinate covalent bonds must have a lone pair and almost always involve a transition metal, we can immediately narrow the choices to Answers B and D because PCl5 is covalent and CH4 doesn't have a lone pair. The first item in both lists qualifies as ionic, so move on to the second, which should be a covalent bond. Lead Nitrate is clearly an ionic compound, so D is out and the answer must be B. Don't be worried about the positive charge on the ammonium compound. The N-H bonds are still covalent and this is not changed by the fact that they happen to have a formal charge (Had the NH4+ been paired with an anion, then it would have been an example of an ionic bond).
A student is studying an unknown compound XY. Which of the following observations would provide the best evidence that the unknown compound is an ionic compound?

A. a solution of XY conducts electricity
B. XY has a relatively low boiling point
C. XY is a solid at room temperature
D. X and Y are found to have different electronegativities
C; Answer A is true of ionic compounds, they do conduct electricity well when dissolved in solution, but covalently bonded pairs such as HCl also do this when dissolved in solution. Answer B is the exact opposite of what would be expected from an ionic compound, they have very high boiling points. Answer C makes sense, because essentially all ionic compounds are solids at room temperature. Answer D is also true of ionic compounds, but is true of the majority of covalent compound as well. Had the answer choice read "large differences in electronegativity," that would have been more characteristic of an ionic compound.
Which of the following statements concerning quantum numbers is NOT entirely accurate?

A. The principle quantum number is proportional to the energy level of the atom
B. The azimuthal quantum number describes the subshell where the electron is located
C. The magnetic quantum number specifies which of the orbitals holds the electron
D. The electron spin quantum number differentiates between two electrons in the same orbital
A; A is only generally true. Recall that a 3d orbital is actually higher in energy than a 4s. The remaining three answer choices are all completely accurate regarding quantum numbers—make sure you know them!
Which of the following statements is/are NOT true of the equilibrium constant, Keq?

I. Increasing temperature changes Keq
II. Increasing temperature has no effect on Keq
III. Changing the initial concentration of products or reactants changes Keq

A. I only
B. II & III
C. III only
D. I, II & III
B; Understanding K is very important to doing well on the MCAT. Recall that K is a "snapshot" of equilibrium that tells us where it is located and what it looks like. As far as the MCAT is concerned, temperature is the ONLY thing that changes K. Statement I is true because temperature does actually "move" the equilibrium point. Statement II is thus false because it says the exact opposite. Statement III is false because K is a ratio of products over reactants AT EQUILIBRIUM and has nothing to do with how much of each you started with. (NOTE: Don't confuse what we said about shifting K with LeChatelier's principle. Le Chatelier's principle DOES NOT deal with moving K. It just says that K will ALWAYS be the same place and if you cause a disturbance that makes the ratio of products to reactants no longer equal to K, the reaction will proceed in whatever direction gets it back to K).
28. Solid Sr metal reacts exothermically with water, releasing heat and a colorless gas. The most likely identity of the gas and the electron configuration of the resulting metal ion are:

A. H2(g); [Ar] 4s23d104p6
B. H2O(g); [Ar] 4s23d104p6
C. H2(g); [Ar] 4s23d104p65s2
D. SrO2(g); [Ar] 4s23d104p65s1
A; These "identify the gas" problems can be tricky. Always try to narrow your choices first by ruling out gases that would be impossible (i.e., they contain elements that aren't even in the reaction) or seem very illogical. Next, look at the actual molecules involved and figure out how they would have to break up and re-bond in order for each remaining gas. Often you will see illogical things happening here too. Remember that reactions don't occur spontaneously unless something favorable is happening. Also remember that water is VERY often a product or reactant in these reactions. It may help to ask yourself, "If I formed water or used water, what would be left over?" In this case, you are helped by the electron configuration. You should know that since a lot of energy is being released, Sr is probably going to a much lower energy state, such as its noble gas configuration. This tells you the electron configuration should end in 4p6. That narrows it down to A or B. Is it likely that if Sr reacts violently WITH water that the gas they are describing is just water vapor? No, so A must be the correct answer.
Calcium reacts violently with water and evolves a gas in the process. Which of the following equations most likely represents the reaction between calcium metal and water?

A. Ca2+ + H2O(l) H2(g) + CaO(s)
B. Ca(s) + 2H2O(l) Ca2+ + H2(g) + 2OH-
C. Ca(s) + H2O(l) H2O(g) + Ca2+
D. Ca2+ + 2H2O(l) Ca(s) + 2H2(g) + O2(g)
30) B; Don't be intimidated by this type of question. Look at your possibilities and rule out nonsense. Since we were told that Calcium, not calcium ions, is reacting with water, rule out A and D. Answer choice B shows water turning from liquid to vapor apparently spontaneously as solid calcium loses two electrons to form Ca2+. If you didn't know it already, REDOX reaction always occur in pairs. Things don't lose electrons unless they go ONTO somebody else who is reduced. As a good exercise, try tracking where the electrons are going in the reaction for Answer B, which is the correct answer.
32. When a solution of FeCO3 ¬and water is mixed with HBr, a gas is produced. This gas is most likely:

A. CO2
B. H2O (water vapor)
C. H2
D. Br2
A; To help you solve this problem, write out the reactants. You have Fe2+ with water, CO32- and HBr. Using a little O-Chem knowledge will help you here even though this would show up on the PS section. The oxygens on the carbonate would make good nucleophiles and the H on the HBr a good electrophile. To know you've figured out what is actually happening on one of these "which gas is produced" questions, you usually need to be able to account for what happens to each species. First, you will learn in the O-Chem section that decarboxylation, the forming of CO2, is a very energetically favorable reaction. If one of the oxygens on carbonate gained two H's from two HBr molecules, water could leave and CO2 would be formed. The iron and bromine ions could then combine, which sounds logical because you've probably seen FeBr2 before. That accounts for all the species in a logical way and that happens to be exactly what occurs. In general, all acids react with metal carbonates to form CO2 and the related salt. However, that is something way too specific to waste your time memorizing for the MCAT. If one of these types of questions does show up on your actual MCAT, it probably won't be about carbonates anyway—it will be some other gas producing reaction. You really can't memorize the thousands of such reactions that exist, so you'll need to depend on logic and attempting to account for what happens to each species.
Transition metals, such as Fe, Cu and Co, often form brightly colored solutions when mixed with water. Which of the following best accounts for this observation?

A. Fe(s) and Co(s) have unfilled d orbitals, which emit visible light when excited
B. Fe and Co ions have partially filled d orbitals and electrons in these orbitals absorb visible light
C. Fe(s) and Co(s) are blue and green, respectively, in their elemental state
D. Fe and Co ions are positively charged and thus have an electrostatic attraction for photons
B; You should be aware of the few limited things that can cause light, color, phosphorescence, etc. in chemistry. Whenever actual light or photons are emitted, it has to be because electrons are relaxing from a higher to a lower energy level and releasing the extra energy as a photon. A somewhat different thing can happen with transition metals. They have partially filled d orbitals that allow for electrons to absorb a lot of different wavelengths of light. Usually, they will absorb nearly all of the white light, EXCEPT for a few wavelengths, resulting in a dull to rich color, most often blue or green (although other colors are seen). This color is NOT the result of light being emitted, but the result of the few wavelengths of UNABSORBED light being reflected. Very bright colors that are fluorescent, phosphorescent, or that show up in things like flame tests, are usually the former kind due to actual photon emission. The duller colors seen in solution chemistry are almost always the later kind, due to partially filled d orbitals in transition metals. This makes B the most logical answer.
Which of the following compounds is likely to have a vapor pressure closest to that of acetone?

A. CH3SOCH3
B. CH3SiOCH¬3
C. CH3NOCH3
D. CH3CHOHCH3
B; Whenever you are asked for "another element" that will react "similarly" to a given element, the right answer will almost always be an element in the same family or group. Although elements in the same period and only differing by one proton may be more similar in size, reactivity and physical characteristics are most similar among elements in the same family. Answer A is just acetone with carbon being replaced with sulfur. This is possible, but B is a better answer because Silicon is just below carbon in the periodic table. Nitrogen is not in the same family, making answer C unlikely. Finally, answer D is an alcohol, which would be expected to have entirely different properties than a ketone such as acetone.
A chemist prepares a solution by adding 200mL of 0.80M Fe2(SO4)3 to 2.0 L of water. How many moles of sulfate ions are present?

A. 1.6 x 10-1
B. 4.8 x 10-1
C. 4.8 x 102
D. 1.6 x 102
B; This is a mole-to-mole conversion problem. They should be pretty straightforward, but they are often missed. Make sure you UNDERSTAND how to do them, then focus on not making dumb math mistakes. You will definitely see a few on your MCAT. In this case, multiply the M (moles/L) by the volume in liters (0.2L) to get 0.16 moles of Fe2(SO4)3. If you forget to change milliliters to Liters, you'll get the wrong answer. Next, you must notice that for every one mole of iron sulfate there are 3 moles of sulfate ions. Multiplying the previous answer by 3 gives Answer B, 0.48, or 4.8 x 10-1.
How many hydrogen atoms are present in 2.0 grams of water?

A. 1.33 x 1023
B. 6.67 x 10-1
C. 6.67 x 1022
D. 2.22 x 10-1
A; Once again, simple mole-to-mole stuff. Convert grams of water into moles of water by dividing by the molecular weight of water (18 g/mol). Next multiply by the factor 2 moles H atoms/1 mole of H2O. This cancels moles of water and leaves you with moles of H atoms. However, the question does NOT ask for moles of H atoms, it asks for how many; thus, you must multiply by Avogadros number, 6 x 1023. This gives Answer A.
A student accidentally uses an unclean beaker to begin an experiment. The last student to use the beaker left an almost unnoticeable 3.0mL of HCl in the beaker. If the student must report the total moles of HCl formed by the experiment, by how many moles will his data be in error? (assume T = 25°C; DensityHCl = 1.21 g/cm3)

A. 0.98
B. 0.098
C. 0.3
D. 0.03
B; This is, guess what, another mole-to-mole problem. Moles are often hidden, however. Remember from the lessons that you can be given moles in the form of a density and a volume, in molarity and volume, or in PV=nRT. In this case, multiply 3 mL by 1.2 g/mL (note that cm3 = mL) to get 3.6 grams. Now, divide by the molecular weight of HCl (36.5 g/mole) to get approximately 0.1. You'd be best to use scientific notation to do so. However, now you must be careful not to equate 0.98 with 0.1. The answer is B, 0.098, which is very close to 0.1.
Which of the following steps must increase the percent yield during the base catalyzed decarboxylation of CH3COCH2COOH?

A. Increasing the amount of base
B. Increasing the temperature
C. Removing CO2
D. Increasing the initial concentration of CH3COOCH3
C; The question is basically asking for which action will increase the yield of CO2. Recall that yield can be increased by removing product as it is formed. Overall amount of product can be increased (sometimes called yield), but % yield CANNOT be increased, by adding more reactants. Of course, if one reactant is in excess and one is limiting, then only adding limiting reagent will have any effect. Answers A and C are both just adding reactants. Answer B will increase rate, but not yield. This makes C the best answer.
An electron moves from the n = 4 to the n = 3 energy level. Which of the following gives the frequency of the photon emitted in terms of h?

A. 2.6 x 10-19/h
B. 2.6 x 10-19*h
C. 3.1 x 10-19/h + Ф
D. 3.1 x 10-19/h
A; The key to this question is recalling the formula for the energy of a photon, E = hf. The frequency in terms of h will be f = E/h. The energy of the photon will be equal to the energy difference between the two energy levels. In this case, 31 x 10-20 - 5 x 10-20 = 26 x 10-20, or 2.6 x 10-19. This rules out Answers C and D. As demonstrated, the energy should be divided by h, not multiplied.
In Trial 1, the students bombard a sample of Fe with photons of frequency f and electrons are ejected. If, in a second trial, they increase the frequency of photons used, which of the following will result?

A. the number of electrons ejected will increase
B. the speed of the electrons leaving the iron will increase
C. the current created by the emitted electrons will increase
D. the number of electrons ejected will decrease, but the energy of each electron will increase
B; According to the equation given in the passage, if the frequency of a photon is increased, the energy left over for kinetic energy will increase. We know that the light added must have enough energy to exceed the work function because the stem tells us electrons were ejected in Trial 1. This makes B the best answer. Answers A and C are two ways of saying that more electrons are ejected. More electrons will NOT be ejected; those ejected will just have more energy. Answer D is just plain silly =).