AP Bio semester 1

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-Made up of cells
-all use some sort of energy
-all contain genetic information
-all replicate either sexually or asexually
-all have the capacity to evolve

Five fundamental characteristics of living things

Atoms are little bubbles of space with mass concentrated at the center of the bubble (c)

Atom's physical structure:
a) An atom is a solid mass of material
b) the particles that form an atom are equidistant from each other
c) Atoms are little bubbles of space with mass concentrated at the center of the bubble
d) Atoms are little bubbles of space with mass concentrated on the outside surface of the bubble

A nonpolar covalent bond (c)

When the atoms involved in a covalent bond have the same electronegativity, what type of bond results?
a) an ionic bond
b) a hydrogen bond
c) a nonpolar covalent bond
d) a polar covalent bond

Hydrogen bond formed between the hydrogen of one water molecule and the oxygen of another water molecule (c)

Water has a high specific heat because of the...
a) polar covalent bond formed between the oxygen and a hydrogen of a single water molecule
b) ionic bonds formed between the hydrogen of one water molecule and the oxygen of another water molecule
c) Hydrogen bond formed between the hydrogen of one water molecule and the oxygen of another water molecule
d) covalent bond formed between the hydrogen of one water molecule and the oxygen of another water molecule

Energy in the form of sunlight or heat was transformed into chemical energy (a)

Which statement best summarizes the essence of chemical evolution?
a) Energy in the form of sunlight or heat was transformed into chemical energy
b) instead of being radiated back to space, energy in the form of sunlight or heat was retained in the oceans and atmosphere because of water's high specific heat
c) entropy increased
d) an increasing number of exothermic reactions occurred

Higher temperature and concentration tend to increase the rate of chemical reactions.

Higher __________ and ____________ tend to increase the rate of chemical reactions.

Nucleus

-Eukaryotic Animals and plants
-Info storage and DNA
-chromosomes coiled, tightly wound
-proteins from the genes (usually)

Ribosome

-Eukaryotic A/P and Prokaryotic
-Protein synthesis

Rough ER

-Eukaryotic A/P
-Protein synthesis and processing to golgi apparatus
-bumpy ribosomes
-glycosylation inside

Smooth ER

-Eukaryotic A/P
-Lipid synthesis or breakdown
-Ca+ storage

Golgi apparatus

Eukaryotic A/P
-protein processing and glycosylation
-Cis first then trans next
-stacks

Lysosome

Eukaryotic Animals and possibly plants
-digestion and recycling
-hydrolysis site
-golgi provides the enzymes

Peroxisome

Eukaryotic A/P
-oxidation reactions produce H2O2, then catalase breaks it further

Vacuole

Eukaryotic A/P
-storage space, especially in plants
-turgor pressure high
-osmosis makes it happen, with pigments and toxins

mitochondria

Eukaryotic A/P
-site of aerobic respiration
-ATP produced

Chloroplasts

Eukaryotic plants
-site of photosynthesis

cytoskeleton

Eukaryotic A/P
-Structural: actin, intermediate filaments and microtubules
-3 types of filaments: shape movement, support, divide

plasma membrane

Eukaryotic A/P
-controls entry/exit, attachment, and communication
-fluid mosaic
-homeostasis maintained

cell wall

Eukaryotic plants and prokaryotes
-structure and support

Cells would have appeared in both flasks (B)

Recall Pasteur's experiment on spontaneous generation. If he had just warmed the nutrient-rich broth, rather than boiled it, what would have been the likely outcome of his experiment?
a) cells would not have appeared in either flask
b) cells would have appeared in both flasks
c) cells would have appeared in the swan-neck, but not the straight-neck flask
d) cells would have appeared in the straight-neck, but not the swan-neck flask

Includes a large number of replicates, a control, and alters only one condition between the controls and the experimental condition (d)

The best experimental design...
a) includes a large number of replicates/trials for each condition
b) includes a control
c) alters only one condition between the controls and the experimental condition
d) Includes a large number of replicates, a control, and alters only one condition between the controls and the experimental condition

Lance Armstrong, because he has reproduced (d)

Lance Armstrong just finished third in the 2009 Tour de France cycling race. This was an incredible feat for the 37-year-old father of 4. First and second-place winners, Alberto Contador (27) and Andy Schleck (24), respectively, have no children. Which of these three men shows the greatest evolutionary fitness?
a) Alberto Contador, because he won the race
b) Lance Armstrong, because he came in third at the advanced age of 37
c) Andy Schleck, because he beat the highly experienced Lance Armstrong
d) Lance Armstrong, because he has reproduced

A reaction that is slightly exothermic and leads to a huge increase in entropy (d)

Which reaction is most spontaneous?
a) a reaction that is slightly exothermic and leads to a slight increase in entropy
b) a reaction that is slightly endothermic and leads to a huge decrease in entropy
c) a reaction that is highly exothermic and leads to a huge decrease in entropy
d) a reaction that is slightly exothermic and leads to a huge increase in entropy

It is included in almost every reaction of life. Because it has 4 valence electrons, it can form a wide variety of molecules. Also, it forms strong bonds with other atoms, thus helping to make it a solid backbone.

Why is carbon so well suited to forming the types of molecules found in living things?

R group-basic shape and structure-->function
functional group-bonding

Explain the relationship of the "R" group and the functional group found on the same molecule.

Carbohydrates

-Function: structure, energy storage, and ID
-Building blocks/monomers: monosaccharides
-Ex. lactose

Lipids

-Function: energy storage, membrane
-monomers: glycerol/fatty acids
-Ex. steroids

proteins

-Function: enzymes
-monomers: amino acids
-Ex. Amylase

Nucleic acids

-Function: genetic information/storage
-monomers: nucleotides
-Ex. DNA, RNA

A phosphorus atom (A)

Which one of the following is not a component of each monomer used to make proteins?
a) a phosphorus atom, P
b) an amino functional group, NH2
c) a side chain, R
d) a carboxyl group, COOH
e) a central carbon atom

The components of the R-group (C)

What aspects of amino acid structure vary among different amino acids?
a) the long carbon-hydrogen tails of the molecule
b) the presence of a central C atom
c) the components of the R-group
d) the glycerol molecule that forms the backbone of the amino acid

The presence of carboxyl and amino groups gives it the ability to form peptide bonds, and its side chain gives it unique chemical properties (c)

How does structure of an amino acid enable it to play its most important roles in cells?
a) it can serve a wide variety of functions in a cell because it contains the atoms most commonly found in organisms (C, H, N, O)
b) Because both carboxyl and amino groups are present, polymerization is exergonic. In addition, the presence of a side chain makes the molecule water soluble
c) The presence of carboxyl and amino groups gives it the ability to form peptide bonds, and its side chain gives it unique chemical properties
d) because each amino acid contains a variety of functional groups, they can participate in a wide variety of chemical reactions

Hydrogen bonds, covalent bonds, glycosylation

Three types of interactions that stabilize the tertiary structure of a protein

Primary structure (a)

You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
a) primary structure
b) secondary structure
c) tertiary structure
d) quaternary structure

Allosteric Regulation

a substance enters the site of the enzyme, changing the shape of the enzyme, not allowing certain substances to be catalyzed

Competitive inhibition

Every enzyme has an active site. A molecule enters and blocks others from getting in

-carries information
-acts as an enzyme, catalyzing information

For what two reasons is RNA thought to be the most likely molecule to have been the first life form to have evolved on Earth?

The strands of the double helix are complementary (c)

In the context of chemical evolution, DNA's structure is interesting because it suggests a possible copying mechanism. What about DNA's structure facilitates copying?
a) it has the same number of adenines and cytosines
b) the nitrogenous bases are located on the inside of the double helix
c) the strands of the double helix are complementary
d) DNA always goes from 5' to 3'

glycogen-long-term energy storage in animals; starch-long-term energy storage in plants; cellulose-cell walls in plants

Examples of polysaccharides and their functions

breaks bacteria apart in humans

Lysozyme, an enzyme found in human saliva and tears, catalyzes the hydrolysis of the glycosidic linkages in pepditoglycan. What effect does this enzyme have on bacteria?

The polar heads interact with water; the nonpolar tails do not (c)

How do phospholipids interact with water molecules?
a) the polar heads avoid water; the nonpolar tails attract water
b) phospholipids don't interact with water because water is polar and lipids are nonpolar
c) the polar heads interact with water; the nonpolar tails do not
d) phospholipids dissolve in water

Ions cannot cross planar lipid bilayers (d)

In an experiment involving planar lipid bilayers, a solution of table salt is added on the left side of the membrane while pure water is added on the right side. After 30 minutes the researchers test for the presence of ions on each side of the membrane. The right side tests negative for ions. What can you conclude?
a) the experiment failed
b) the water somehow blocked the movement of ions across the membrane
c) the left side would probably also test negative for ions
d) ions cannot cross planar lipid bilayers

The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC (d)

What will happen to a red blood cell (RBC), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?
a) nothing
b) the cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC
c) the cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC
d) the cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC

Transmembrane (a)

Rhodopsins are light-sensitive molecules composed of a protein (opsin) and retinal. Opsin is a membrane protein with several helical segments tha loop back and forth through the plasma membrane. Which of the following best describes this particular protein?
a) transmembrane
b) peripheral
c) external
d) internal

Tertiary (c)

Proteorhodopsin consists of a single polypeptide chain. What is the highest level of structure found in this protein?

The sodium-potassium pump is an example of active transport because it moves ions from regions of low concentration to regions of high concentration, requiring the use of ATP, a common energy carrying molecule in all cells.

The sodium-potassium pump is an example of ______ transport because it moves ions from regions of ___ concentration to regions of ____ concentration, requiring the use of ___, a common energy carrying molecule in all cells.

The 20 amino acids serve as a signal sequence that directs the forming polypeptide to the endoplasmic reticulum, where they are cleaved off during processing (b)

Scientists have found that polypeptides that are normally synthesized in the endoplasmic reticulum are about 20 amino acids longer when they are synthesized by ribosomes not attached to the ER. What is the hypothesized explanation for the greater length of these polypeptides?
a) the ribosomes that function as free ribosomes function differently than the ribosomes that are attached to the ER
b) the 20 amino acids serve as a signal sequence that directs the forming polypeptide to the ER, where they are cleaved off during processing
c) the 20-amino-acid sequence helps the ER package these proteins for shipping to the golgi
d) the protein has a different function in the cytosol than in the ER

abnormally shaped RBCs (a)

Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?
a) abnormally shaped RBCs
b) an insufficient energy supply in the RBCs
c) an insufficient supply of oxygen-transporting proteins in the RBCs
d) adherence of RBCs to blood vessel walls causing plaque formation

6 CO2 + 6 H2O + light energy--> C6H12O6 +6 O2

Photosynthesis equation

Light reactions

-Thylokoid membrane
-Sunlight, ADP+P, H20, NADP+H+-->ATP, NADPH, O2
-turns light energy into chemical energy in the form of ATP and NADPH

Calvin Cycle

-Stroma
-3 RuBP, 3 CO2, ATP, NADPH-->6 3-phosphoglycerate, CH2O, G3P (sugars), 3 RuBP, H2O, ADP+P, NAD++H+
-Carbon dioxide fixation-->reduction to G3P-->Regeneration of RuBP

C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + 38 ATP

Cellular Respiration equation

Glycolysis

-Cytosol
-glucose-->2 pyruvate, 2 NADH, 2 ATP
-breaks glucose in half and extracts a little energy from glucose

Acetyl CoA formation

-mitochondrial matrix
-pyruvic acid-->2 CO2, 2NADH, 2 Acetyl CoA
-pyruvate enters the krebs cycle after being modified and combining with Acetyl CoA

Citric Acid Cycle

-mitochondrial matrix
-2 Acetyl CoA--> Electron carriers (NADH and FADH2), CO2, ATP
-series of reactions that continues oxidation of C6H12O6 to create e- carrier molecules

Electron transport

-Mitochondrial membranes
-NADH, FADH2, O2-->ATP, H2O
-Electrons are passed through a chain of electron carriers, resulting in a charge gradient... chemiosmosis-->spins ATP synthase

Most of the CO2 from the catabolism of clucose is released during the Krebs cycle (d)

Most of the CO2 from the catabolism of glucose is released during...
a) glycolysis
b) electron transport
c) chemiosmosis
d) the Krebs cycle

NADH (d)

Following glycolysis and the Krebs cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of...
a) acetyl-CoA
b) glucose
c) pyruvate
d) NADH

In the energy-yielding phase of glycolysis, energy is extracted in the form of ATP and NADH (D)

In the energy-yielding phase of glycolysis, energy is extracted in the form of...
a) pyruvate
b) ATP
c) NADH
d) ATP and NADH

NADH and FADH2 (d)

Which electron carrier(s) function in the Krebs cycle?
a) NAD+ only
b) both NAD+ and FAD
c) the ETC
d) NADH and FADH2

The rates of ATP production and carbon dioxide production would both increase (b)

If you were to add one or more of the eight Krebs cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to their rates of ATP and carbon dioxide production?
a) There would be no change in ATP production, but we would observe an increased rate of carbon dioxide production
b) the rates of ATP production and carbon dioxide production would both increase
c) the rate of ATP production would decrease, but the rate of carbon dioxide production would increase
d) rates of ATP and carbon dioxide production would probably both decrease

The krebs cycle is an unregulated reaction cycle (b)

Which of the following statements about cellular respiration is false?
a) glycolysis is inhibited when cellular energy levels are abundant
b) the Krebs cycle is an unregulated reaction cycle
c) in the ETC, electrons decrease in energy level as they are transferred from one electron carrier to the next
d) reactions of the Krebs cycle take place in the mitochondrial matrix

The first CO2 that is released during aerobic cellular respiration is between glycolysis and the Krebs cycle (b)

The first CO2 that is released during aerobic cellular respiration is...
a) during glycolysis
b) between glycolysis and the Krebs cycle
c) during the Krebs cycle
d) just after the Krebs cycle

The extraction of energy from high-energy electrons remaining from glycolysis and the Krebs cycle (C)

Which of the following events takes place in the electron transport chain?
a) breakdown of glucose into two pyruvate molecules
b) the breakdown of an acetyl group to carbon dioxide
c) the extration of energy from high-energy electrons remaining from glycolysis and the krebs cycle
d) substrate-level phosphorylation

In the electron transport chain (d)

glucose + 6 O2-->6 carbon dioxide + 6 H2O: where is most of the water in this reaction produced?
a) during glycolysis
b) in the Krebs cycle
c) during fermentation
d) in the electron transport chain

The electron transport chain is a series of redox reactions (a)

The electron transport chain...
a) is a series of redox reactions
b) is a series of substitution reactions
c) is driven by ATP consumption
d) takes place in the cytoplasm of eukaryotic cells

The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in mitochondria (B)

The energy of electron transport serves to move (translocate) protons to the outer mitochondrial compartment. How does this help the mitochondrion to produce energy?
a) the hydrogen ions (protons) are transferred to oxygen in an energy-releasing reaction
b) the translocation of protons sets up the electrochemical gradient that drives ATP synthesis in the mitochondria
c) the protons pick up electrons from the electron transport chain on their way through the inner mitochondrial membrane
d) the protons receive electrons from the NAD+ and FAD that are accepted by electrons in glycolysis and the Krebs cycle

They allow the cell to conserve oxygen for the Krebs cycle (C)

Why are fermentation reactions important for cells?
a) they produce alcohol which enhances the permeability of their mitochondrial membranes to proton translocation
b) they regenerate NAD+ so that glycolysis can continue to operate
c) they allow the cell to conserve oxygen for the Krebs cycle
d) they generate oxygen

They directly enter the Krebs cycle (d)

Fatty acids usually have an even number of carbons in their structures. They are catabolized by a process called beta-oxidation. The end products of this metabolic pathway are acetyl groups of acetyl CoA molecules. What is the most likely fate of the acetyl groups?
a) they directly enter the electron transport chain
b) they directly enter the energy-yielding stages of glycolysis
c) they are directly decarboxylated by pyruvate dehydrogenase
d) they directly enter the Krebs cycle

Ubiquinone is lipid soluble and so can move through the inner mitochondrial membrane while carrying electrons and shuttling protons across the membrane (d)

The constituents of the electron transport chain have similar capabilities, with the exception of ubiquinone (coenzyme Q). What is different about ubiquinone?
a) Ubiquinone is a protein that begins the electron transport chain, so it accepts the highest-energy electrons
b) Ubiquinone is a protein that serves as a regulator of the rate of redox reactions in the ETC
c) Ubiquinone is a protein that is a constituent of all cells, prokaryotic or eukaryotic; hence its name originating from ubiquitous
d) Ubiquinone is lipid soluble and so can move through the inner mitochondrial membrane while carrying electrons and shuttling protons across the membrane

Chemiosmosis is an important concept in our understanding of cellular metabolism in general because it explains how ATP is synthesized by a proton motive force (a)

Chemiosmosis is an important concept in our understanding of cellular metabolism in general because...
a) it explains how ATP is synthesized by a proton motive force
b) it explains how electron transport can fuel substrate-level phosphorylation
c) it explains the sequence of the electron transport chain molecules
d) it explains the reduction of oxygen to water in the final steps of oxidative metabolism

They contain a fluid-filled space called stomata (a)

Which of the following statements concerning chloroplasts is false?
a) they contain a fluid-filled space called stomata
b) they have both outer and inner membranes
c) they have their own DNA
d) they have an internal membrane system known as the thylakoid

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from glucose (b)

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from...
a) water
b) glucose
c) air
d) electrons from NADPH

Blue and red (b)

Chlorophylls absorb light in which colors of the visible range?
a) green and blue
b) blue and red
c) green and red
d) violet and red

In addition to proteins, thylakoid membranes must contain a large number of pigment molecules in the reaction centers in order to harvest light energy (C)

In addition to proteins, thylakoid membranes must contain a large number of _______ molecules in the reaction centers in order to harvest light energy.
a) phospholipid
b) water
c) pigment
d) electron carrier

Chlorophyll a and b absorb light energy at slightly different wavelengths (d)

Which of the following is a difference between chlorophyll a and chlorophyll b?
a) chlorophyll a is a pigment, and chlorophyll b is the enzyme that transfers excited electrons from chlorophyll a to electron carriers of the thylakoid membrane
b) chlorophyll a absorbs yellow light, and chlorophyll b absorbs green
c) chlorophyll a contains a Mg in its ring structure, whereas chlorophyll b contains iron
d) chlorophyll a and b absorb light energy at slightly different wavelengths

This setup enables the plant to absorb light energy of a variety of wavelengths (b)

Why are there several structurally different pigments in the reaction centers of photosystems?
a) excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain
b) this setup enables the plant to absorb light energy from a variety of wavelengths
c) they enable the plant to absorb more photons from light energy, all of which are at the same wavelength
d) they enable the reaction center to excite electrons to a higher energy level

the carotenoids and other pigments are still visible in the leaves (a)

In autumn, the leaves of deciduous trees change colors. This is because the chlorophyll is degraded, and...
a) the carotenoids and other pigments are still visible in the leaves
b) degraded chlorophyll changes color
c) water supply to the leaves has been reduced
d) the cells of the leaves begin to die

Carotenoids probably have a protective function in the cell (b)

Energy from sunlight can excite electrons, kicking them out of their orbitals and creating free radicals. Free radicals are highly reactive atoms or molecules that have unpaired electrons and degrade and destroy other compounds in their vicinity. Carotenoids, one of the pigments present in most chloroplasts, can stabilize these free radicals. This suggests that...
a) once chloroplasts are destroyed, the free radicals will destroy the cell
b) carotenoids probably have a protective function in the cell
c) free radicals induce the synthesis of carotenoids in chloroplasts
d) carotenoids communicate directly with the immune system of plants

An electron is excited (d)

What event occurs just after energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?
a) ATP is synthesized from the energy absorbed
b) a carboxylation reaction of the Calvin Cycle occurs
c) Electrons are stripped from NADPH
d) An electron is excited

It is used to establish and maintain a proton gradient (c)

As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy?
a) it excites electrons of the reaction center of P1
b) It is lost forever
c) it is used to establish and maintain a proton gradient
d) it is used to phosphorylate NAD+ to NADPH, the molecule that accepts electrons from p1

Water (C)

The electrons of p2 are excited and transferred to electron carriers. From which molecule or structure do the p2 replacement electrons come?
a) the electron carrier, plastocyanin
b) p1
c) water
d) oxygen

The products of light-dependent reactions are used in light-independent reactions (b)

How are the light-dependent and light-independent reactions of photosynthesis related?
a) The products of the light-independent reactions are used in the light-dependent reactions
b) the products of light-dependent reactions are used in light-independent reactions
c) The products of light-independent reactions must be present for light dependent reactions to take place
d) they are not related

To produce NADPH and ATP (c)

What is the main purpose of the light-dependent reactions of photosynthesis?
a) to generate oxygen by splitting H2O
b) to produce NADPH for use in respiration
c) to produce NADPH and ATP
d) to use ATP to make glucose

Rubisco is a very slow enzyme; what it lacks in speed, it makes up in quantity (b)

Data suggest that rubisco makes up 10% of the total protein found in spinach leaves. Research elucidating the structure of rubisco shows that it has 4 active sites. Why, with four active sites, might there be such a large concentration of rubisco in plant matter?
a) all heterotrophic organisms depend on plants, either directly or indirectly, for their food supply
b) Rubisco is a very slow; what it lacks in speed, it makes up in quantity
c) rubisco catalyzes four of the six reactions found in the Calvin Cycle
d) three of the four active sites bind carbon dioxide; only one binds ribulose-1, 5-biphosphate

Photosynthesis stores energy in complex organic molecules; respiration releases the energy stored in complex organic molecules (d)

Which of the following statements most accurately compares photosynthesis and respiration?
a) ATP generated during photosynthesis is a fundamentally different process than ATP generated during respiration
b) photosynthesis is just respiration in reverse
c) photosynthesis requires ATP, but respiration does not
d) Photosynthesis stores energy in complex organic molecules; respiration releases the energy stored in complex organic molecules

A single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally (d)

Which of the following contradicts the "one-gene, one-enzyme hypothesis"?
a) a mutation in a single gene can result in a defective protein
b) alkaptonuria results when individuals lack a single enzyme involved in the catalysis of homogentistic acid
c) sickle-cell anemia results in defective hemoglobin
d) a single antibody gene can code for different related proteins, depending on the splicing that takes place post-transcriptionally

At lease in some cases, a single gene must code for more than one protein (c)

The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?
a) this finding lends support to the one-gene, one-enzyme hypothesis
b) the number of monomeric subunits found in proteins is fewer than the number of monomeric subunits found in genes
c) at least in some cases, a single gene must code for more than one protein
d) noncoding DNA is important in determining the proteome

The three-base sequence of mRNA (c)

Which of the following is directly related to a single amino acid?
a) the base sequence of the tRNA
b) the amino acetyl tRNA synthase
c) the three-base sequence of mRNA
d) the complementarity of DNA and RNA

Genotype is to DNA base sequence as phenotype is to amino acid sequence (a)

Genotype is to ______ as phenotype is to _____
a) DNA base sequence; amino acid sequence
b) heredity; DNA base sequence
c) gene regulation; translation
d) transcription; amino acid sequence

mRNA because it transfers information from DNA (c)

According to the central dogma, what molecule should go in the blank? DNA-->____-->proteins
a) mRNA because it makes proteins directly
b) rRNA because it makes proteins directly
c) mRNA because it transfers information from DNA
d) tRNA because it transfers information from DNA

To determine the role of proteins coded for by those genes that are knocked out (b)

Knockout mice have been genetically altered to knock out specific genes. How are these mice most often used in research?
a) to study DNA replication in the defective genes (those that have been altered)
b) to determine the role of proteins coded for by those genes that are knocked out
c) to examine defects in DNA structure in those regions that have been altered
d) to study the effect of radiation on DNA

RNA is synthesized (b)

In the process of transcription:
a) DNA is replicated
b) RNA is synthesized
c) proteins are synthesized
d) mRNA attaches to ribosomes

A-A-A-A-A; nucleus

Given the DNA template T-T-T-T-T, which of the following bases would you find in a complementary RNA strand and where would they be synthesized?
a) A-A-A-A-A; nucleus
b) U-U-U-U-U; nucleus
c) A-A-A-A-A; ribosome
d) U-U-U-U-U; ribosome

mRNA (b)

Codons, the three base sequences that code for specific amino acids, are part of...
a) protein
b) mRNA
c) tRNA
d) rRNA

Only a single amino acid could change, because the reading frame is unaffected (a)

How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene, and why?
a) only a single amino acid could change, because the reading frame is unaffected
b) the amino acid sequence would be substantially altered, because the reading frame would change with a single base substitution
c) all amino acids following the substitution would be affected, because the reading frame would be shifted
d) it is not possible for a single base substitution to affect protein structure, because each codon is three bases long

If RNA polymerase is missing sigma then transcription initiation would not occur (c)

If RNA polymerase is missing _____ then transcription initiation would not occur
a) amino acids
b) tRNA
c) sigma
d) the holoenzyme

Promoters (d)

Which of the following is part of a DNA molecule?
a) sigma
b) the holoenzyme
c) initiation factors
d) promoters

They bind the sigma subunit that is associated with RNA polymerase (b)

David Pribnow studied the base sequences of promoters in bacteria and bacterial viruses. He found two conserved regions in these promoters (the -10 box and the -35 box). What is the function of these two regions of the promoter?
a) they signal the initiation site
b) they bind the sigma subunit that is associated with RNA polymerase
c) they attach the correct nucleotide triphosphate to the template DNA strand
d) they separate the two DNA strands

binding of sigma to the promoter region (a)

Which of the following processes is central to the initiation of transcription?
a) binding of sigma to the promoter region
b) formation of a phosphodiester bond in the elongating RNA strand
c) binding of DNA polymerase to the promoter region
d) formation of a DNA primer

A primary mRNA transcript in the nucleus of a eukaryotic cell is longer than the functional mRNA, while a primary transcript in a prokaryotic cell is the same size as the functional mRNA (b)

A primary mRNA transcript in the nucleus of a eukaryotic cell is _____ the functional mRNA, while a primary transcript in a prokaryotic cell is ___ the functional mRNA?
a) the same size as; the same size as
b) longer than; the same size as
c) longer than; smaller than
d) the same size as; longer than

Post-transcriptional modification removes the introns (b)

mRNA is smaller than the length of the DNA that codes for it because...
a) the regulatory regions (introns) of the gene are not transcribed
b) post-transcriptional modification removes the introns
c) post-transcriptional modification removes the exons
d) bases are added to the tail of the primary transcript

RNA polymerase termination (d)

Which of the following does not occur in post-transcriptional modifications occurring in eukaryotic mRNAs?
a) addition of poly A tail
b) addition of methyl-guanosine cap
c) removal of introns
d) RNA polymerase termination

Codons are a nearly universal language among all organisms (d)

Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?
a) Prokaryotic codons usually contain different bases than those of eukaryotes
b) Prokaryotic codons usually specify different amino acids than those of eukaryotes
c) the translation of codons is mediated by tRNAs in eukaryotes, but translation requires no intermediate molecules such as tRNAs in prokaryotes
d) Codons are a nearly universal language among all organisms

Concurrent transcription and translation (b)

Which of the following occurs in prokaryotes, but not eukaryotes?
a) post-transcriptional splicing
b) concurrent transcription and translation
c) translation in the absence of a ribosome
d) gene regulation

An anticodon forms hydrogen bonds with the codon; it must match the first two bases of the codon, but is less specific with respect to the third base (b)

There are 61 codons that each specify the addition of a specific amino acid, and three stop codons for which there is no corresponding amino acid. However, there are only about 40 tRNA molecules, representing 40 anticodons. How is that possible?
a) only about 40 of the recognized 61 codons are present in mRNA
b) an anticodon forms hydrogen bonds with the codon; it must match the first two bases of the codon, but is less specific with respect to the third base
c) there are tRNAs that can bind one of two related amino acids

Formation of a peptide bond (d)

Which of the following is not one of the steps in initiation of prokaryotic translation?
a) binding of the large ribosomal subunit to the small ribosomal subunit
b) binding of tRNA carrying formyl methionine to the start codon and small ribosomal subunit
c) recognition and binding of mRNA by the small ribosomal subunit
d) formation of a peptide bond

Termination

Step 3 in transcription and translation

Poly A tail

added to 3' end of mRNA

Initiation

Step 1 in transcription and translation

tRNA

carries amino acid to ribosome

Ribozyme

supports RNA world hypothesis

ribosome

site of translation

cap

added to 5' end of mRNA

Crick

proposed wobble hypothesis and existence of tRNA

exons

expressed regions of DNA

RNA polymerase

synthesizes mRNA

elongation

step 2 in transcription and translation

introns

intervening regions of DNA

holoenzyme

sigma plus RNA polymerase

anticodon

portion of tRNA that binds with mRNA

template strand

read by RNA polymerase

snRNPs

proteins and RNA involved in splicing

A P E

three ribosome sites

sigma

binds to promoter region on DNA

Molecular chaperones

assist in post translational folding

The parent cell must first replicate its entire genome (b)

A parent cell divides to form two genetically identical daughter cells in the process of mitosis. For mitosis to take place...
a) the parent cell must maintain its nuclear membrane
b) the parent cell must first replicate its entire genome
c) the parent cell must first undergo cytokinesis
d) the parent cell must divide its DNA in half so that each daughter cell gets only the genes it needs

DNA and proteins (c)

In eukaryotic cells, chromosomes are composed of...
a) DNA and RNA
b) DNA only
c) DNA and proteins
d) DNA and phospholipids

In the S phase of the cell cycle (d)

Scientists isolate cells in various phases of the cell cycle. They find a group of cells that have 1.5 times more DNA than do G1 phase cells. The cells of this group are...
a) between the G1 and S phases in the cell cycle
b) in the G2 phase of the cell cycle
c) in the M phase of the cell cycle
d) in the S phase of the cell cycle

Normal growth and cell function (a)

The first gap in the cell cycle (G1) corresponds to...
a) normal growth and function
b) the phase in which DNA is being replicated
c) the beginning of mitosis
d) the phase between DNA replication and the M phase

Separation of sister chromatids (d)

The mitotic spindle is a microtubular structure that is involved in...
a) splitting of the cell (cytokinesis) following mitosis
b) triggering the compaction and condensation of chromosomes
c) dissolving the nuclear membrane
d) separation of sister chromatids

Cytokinesis (b)

Mitosis is the process of chromosome separation. Cytoplasm is divided between the two daughter cells in a process known as...
a) cloning
b) cytokinesis
c) binary fission
d) G1 phase

Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow (b)

How is plant cell cytokinesis different from animal cell cytokinesis?
a) the cleavage furrow in animal cells is composed of protein contractile filaments; the contractile filaments found in plant cells are structures composed of carbohydrates
b) plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow
c) the structural carbohydrates of the plant cells separate the two cells, whereas in animal cells, a cell membrane separates the two daughter cells
d) Animal cells have centrosome that are involved in this process, but plant cells have microtubule-organizing centers that are not detectable during most of the cell cycle

The cleavage furrow of eukaryotic animal cells (a)

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to...
a) the cleavage furrow of eukaryotic animal cells
b) the cell plate of eukaryotic plant cells
c) the mitotic spindle of eukaryotic cells
d) the microtubule-organizing center of eukaryotic cells

The microtubules elongate and shorten at their kinetochore end (c)

As chromosomes move toward the poles of the daughter cells, the microtubules remained stationary. This result suggests that...
a) the microtubules elongate and shorten at the centrosome end
b) the microtubules overlap, and slide with respect to one another, effectively shortening the microtubules without depolymerizing the actual fiber
c) the microtubules elongate and shorten at their kinetochore end
d) the microtubules are of constant length; centrosomes move farther apart to separate chromosomes

The cells enter mitosis (c)

What happens when MPF (mitosis-promoting factor) is introduced into immature frog oocytes that are arrested in G2?
a) nothing happens
b) the cells undergo meiosis
c) the cells undergo mitosis
d) cell differentiation is triggered

Tumor suppressors (d)

Regulatory proteins that serve to prevent a cell from entering the S phase under conditions of DNA damage are also known as...
a) cyclins
b) cyclin-dependent kinases
c) antibodies
d) tumor suppressors

They are involved in the disassembly of the nuclear envelope (c)

Exposure of zebrafish nuclei to mitotic cytosol resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?
a) they enable the attachment of the spindle microtubules to kinetochore regions of the centromere
b) they are involved in the disassembly and dispersal of the nucleolus
c) they are involved in the disassembly of the nuclear envelope
d) they assist in the movement of the centrosomes to opposite sides of the nucleus

p53 (a)

For cells to divide more rapidly, increased production would likely be required of each of the following proteins except...
a) p53
b) cyclins
c) activated MPF
d) PDGF

Meiosis (c)

Which of the following processes contributes directly to genetic variation?
a) binary fission
b) mitosis
c) meiosis
d) DNA replication

Two (b)

Somatic cells of roundworms have four chromosomes. How many chromosomes would you find in an ovum from a roundworm?
a) four
b) two
c) eight
d) a diploid number

Anaphase I (d)

Homologous chromosomes are separated during...
a) anaphase II
b) prophase I
c) mitosis
d) anaphase I

Sister chromatids separate in mitosis, and homologues separate in meiosis I (a)

What is a major difference between mitosis and meiosis I?
a) Sister chromatids separate in mitosis, and homologues separate in meiosis I
b) DNA replication takes place prior to mitosis, but not before meiosis I
c) Sister chromatids separate in mitosis, and homologues separate in meiosis II
d) only meiosis I results in daughter cells that contain identical genetic information

Prophase I

Crossover, the exchange of segments of homologous chromosomes, takes place during which of the following phases?
a) prophase II
b) metaphase I
c) anaphase I
d) prophase I

Carry information for the same traits (b)

Homologous chromosomes...
a) are identical
b) carry information for the same traits
c) carry the same alleles
d) align on the metaphase plate in meiosis II

8 (c)

The egg of a fruit fly has 4 chromosomes. How many chromosomes are in a somatic cell of a fruit fly?
a) 4
b) 2
c) 8
d) 16

None. DNA replication occurs before meiosis I begins (d)

At what stage of meiosis does DNA replication take place?
a) DNA replication does not take place in cells destined to undergo meiosis
b) prophase I
c) between meiosis I and meiosis II
d) none. DNA replication occurs before meiosis I begins

19 (c)

Quaking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common but when it does happen the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
a) 9
b) 10
c) 19
d) 38

16 (c)

The diploid number of a roundworm species is 4. You have a male and a female roundworm that are planning a family. Assuming there is no crossover, and random segregation of homologues during meiosis, how many possible combinations of chromosomes might there be in the offspring?
a) 4
b) 8
c) 16
d) 64

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