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BIOL 246 - exam 2

Terms in this set (185)

lowers the activation energy of a reaction
is not used up in a chemical reaction
is a protein (or a ribozyme)

activation energy

the minimum amount of energy required to start a chemical reaction

induced fit model

Change in the shape of an enzyme's active site that enhances the fit between the active site and its substrate(s)

lock and key model

The model of the enzyme that shows the substrate fitting perfectly into the active site

Ending materials in a chemical reaction

cell enzymes, specific to certain organs, that differ slightly in structure, but have similar functions

The part of an enzyme or antibody where the chemical reaction occurs

Rate of enzymatic reaction is affected by:

temperature
pH
concentration of the enzyme

Minerals that assist in the normal functioning of enzymes (metal ions)

vitamins that assist in the normal functioning of enzymes by moving hydrogen ions

converted to a functioning enzyme after the addition or removal of a phosphate (secreted in an inactive form)

metabolic pathway

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product.

allosteric inhibition & end product inhibition

regulated by negative feedback

allosteric inhibition

product of an enzymatic reaction blocks an earlier step in the enzymatic pathway (causes a change in active site shape)

reversible enzymatic reactions are regulated by the _____ of molecules for each reaction

law of mass action

when a chemical reaction moves from the side with a higher concentration to the side with a lower one

Tay-Sachs disease

results from an inborn error in metabolism

Phosporylation/Dephosphorylation

part of conversion of a zymogen to a functioning enzyme

direction of reversible enzymatic reactions

regulated by the relative concentration of products and reactants

result of lack of melanin (inborn error of metabolism)

coupled reactions

are inefficient and result in heat loss
provide the cell the energy it needs for reactions

universal biological energy carrier
form of chemical energy
energy released from an exergonic reaction

reduced molecule

gains electrons

oxidized molecule

loses electrons

final acceptor of electrons in this process of cellular respiration

niacin and riboflavin

necessary for the production of NAD and FAD

Enzymes are named

based on the job or role of the enzyme
with an '-ase' at the end

poison that binds to the enzyme cytochrome c oxidase and inhibits the transfer of electrons from the fourth respiratory complex to oxygen

symptoms of cyanide poisoning

caused by lack of ATP

essential amino acids

cannot be manufactured by the body; must be obtained from food; there are 8

brain's main energy source

where glucose comes from for energy for the brain

Aerobic cell respiration

1) glycolysis
2) citric acid cycle
3) electron transport

Myocardia Ischemia

inadequate blood flow to the heart muscle

death of tissue

angina pectoris

pain in the chest and left arm

TCA
Krebs
citric acid

genetic mutation in the gene that codes for ATP synthase

decrease in ATP production

enzyme that catalyzes the addition of a phosphate to adenosine diphosphate

molecules typically used in aerobic respiration to form ATP

proteins
lipids
glucose

How is aerobic respiration affected if cells have all the ATP they need?

- glucose is converted into glycogen
- glucose is converted into fat
- ATP production is inhibited

formation of fat from excess glucose

where the vast majority of energy is found stored in the body

enzyme that catalyzes lipolysis

Which type of adipose tissue functions in thermogenesis?

remainder of energy is stored as:

process of hydrolyzing triglycerides into glycerol and fatty acids

The reasons humans inhale oxygen is so it can be used for:

making ATP
aerobic respiration

phosphorylation

the addition of a phosphate group to a molecule

Events of Glycolysis

- phosphorylation of glucose
- glucose is broken down into two 3-carbon molecules
- NAD is reduced to NADH
- ATP is formed

synthesis of large molecules such as glycogen and proteins from smaller subunits

An example of catabolism is

the breakdown of glycogen into glucose

glycogen synthase

catalyzes the formation of glycogen from glucose molecules

breakdown of glycogen to glucose

Gluconeogenesis

formation of glucose from noncarbohydrate sources or lactic acid

all catabolic and anabolic reactions within the body

- contribute to diseases and aging
- have unpaired electrons

During glycolysis, one molecule of glucose is broken down into two molecules of:

citric acid cycle

1) guanosine triphosphate (GTP) is produced
2) three molecules of NAD are reduced to NADH
3) one molecule of FAD is reduced to FADH2

How many net ATP molecules are produced per glucose in the lactic acid pathway?

Glycolysis takes place in the

ischemia is usually treated with:

vasodilator drugs

main components of electron transport chain:

cytochromes
flavin mononucleotide
coenzyme Q

to activate glucose at the beginning of glycolysis:

add phosphate
invest energy

anabolic reactions

chemical reactions in the body that require an investment of energy

In cellular respiration, how many ATP molecules can each glucose molecule yield?

In the electron transport system, proton pumps move H+ into the:

intermembrane space of the mitochondria

in the absence of oxygen, glucose is converted to:

active transport

a general process of movement of molecules against a concentration gradient that requires ATP,
involves the movement of molecules from a low concentration to a high concentration

carrier-mediated membrane transport

facilitated diffusion and active transport

Movement of molecules from an area of higher concentration to an area of lower concentration.

rate of diffusion depends on

1. the magnitude of the concentration difference across the membrane ("steepness")
2. the permeability of the membrane to the diffusing substances
3. temperature
4. the surface area of the membrane through which the substances are diffusing

Diffusion of water through a selectively permeable membrane

the effect of a solution on the osmotic movement of water

isotonic solution

no change in volume

the rupture or bursting of red blood cells

shrinking of red blood cells

Non-carrier mediated transport

simple diffusion and osmosis

negatively charged

positively charged

potassium is more concentrated inside the cell compared to other cations because

the membrane is more permeable to it

physiological process that is most directly dependent on membrane potential

measurement of the potential difference of a cell membrane

The extent to which each ion contributes to the potential difference across the plasma membrane—or membrane potential—depends on

(1) its concentration gradient, and (2) its membrane permeability.

For a single ion, the Nernst equation is used to:

calculate the theoretical equilibrium potential of an ion

resting membrane potential

charge difference between the inside and outside of a cell that is not sending any impulses

characteristics of facilitated diffusion

passive transport process
uses a carrier protein
powered by thermal energy

a change in the extracellular concentration of potassium ions

has the greatest effect on resting membrane potential

components that can be found in the extracellular environment

dissolved molecules
proteins
polysaccharides
fluid

substances transferred by blood to interstitial tissue

oxygen
nutrients

extracellular matrix is comprised of

ground substance
elastin fibers
collagen fibers

components found in ground substance

polysaccarides
proteoglycans
glycoproteins
water

functions of integrins

anchor cells to extracellular matrix
relay signals between the cell and extracellular environment

a class of glycoproteins that extend from the cytoskeleton within a cell, through its plasma membrane, and into the extracellular matrix

In order to be stimulated by a hormone, neurotransmitter or paracrine messenger, a cell must possess:

polar regulatory molecules that bind to receptors on the cell membrane

epinephrine
insulin
acetylcholine neurotransmitter

second messengers

polar molecules that bind to receptors without entering the cell to change its activities (ions and cyclic AMP)

cyclic amp is derived from

three protein subunits that shuttle between receptors and different membrane effector proteins, including specific enzymes and ion channels

paracrine, synaptic, endocrine

local secretions, neurotransmitters, hormones

exergonic reaction

reaction that releases energy

amoeboid movement
pseudopods
performed by neutrophils and macrophages

pinocytosis
receptor mediated
is the way cholesterol enters a cell

involved in neurotransmitter release
increases the surface area of cell membrane
releases proteins found in golgi complex

adds water to split molecules

removes phosphate groups

Removes water to join molecules

removes hydrogens

adds phosphate groups

rearranges atoms within a molecule

derived from the vitamin riboflavin

NAD+ is the oxidized state
functions as a hydrogen carrier
is derived from the vitamin niacin

ATP is able to store and release large amounts of energy because of its ________.

high energy bond to the third phosphate group and its ability to couple to exergonic and endergonic reactions

Which of the following correctly represents the mechanism of enzyme function?

E + S -> E-S -> E-P -> E + P

T or F: An enzyme can only bind one reactant at a time.

T or F: An enzyme speeds up a chemical reaction in the cell, but can only be used once.

Where is sucrase found in the human body?

microvilli of the small intestine

The function of sucrase is to ________.

break sucrose into glucose and fructose

How does sucrose change the configuration of sucrase?

Sucrose binds to its active site on sucrase, changing the shape of sucrase enzyme.

How often can a sucrase molecule be used to hydrolyze sucrose?

T or F: the primary role of the citric acid cycle is to complete the oxidation of glucose started by glycolysis.

T or F: The electron transport chain system is responsible for the production of the majority of cellular ATP.

T or F: Since both the liver and skeletal muscle can store glucose as glycogen, both organs can break down the glycogen into free glucose to release into the blood.

T or F: Acetyl coenzyme A enables the products of glycolysis to enter the citric acid cycle.

T or F: The reaction of adenosine diphosphate and phosphate generates adenosine triphosphate and energy.

T or F: Free energy is the only type that can be used to perform cellular work.

Check all that are true statements regarding cell respiration and combustion

as combustion occurs, free energy decreases
as combustion occurs, entropy increases
in each step of cell respiration, energy is released

An individual who was previously sedentary decides to train for a 5-mile race. Over the course of several weeks, his running feels much easier and he is able to run for longer periods of time before experiencing fatigue. Which of the following cellular adaptations can explain his improvement?

Increased mitochondria in adipose cells
Decreased lactic acid production in skeletal muscle
Increased levels of enzymes needed for aerobic cellular respiration

T or F: In the Na+/K+ pump, three sodium ions from inside the cell must enter the carrier first.

Check all of the functions of Antidiuretic Hormone (ADH).

decrease blood osmolality
stimulate water intake
increase water retention

T or F: Glucose enters the cell by the process of facilitated diffusion.

T or F: Osmosis and simple diffusion do NOT require the actions of carrier proteins.

T or F: Facilitated diffusion is unable to transport molecules against a concentration gradient.

Check all of the characteristics shared by carrier proteins and enzymes in the cell membrane.

specificity
saturation
competition

This system is powered by the transport of

The ETS is grouped into __ complexes that serve as _____ pumps.

According to the ________ theory, the electron-transport system (ETS) pumps _____ from the matrix into the space between the inner and outer mitochondrial membrane.

chemiosmotic, protons

The ________ complex transports 4 H₊ from the matrix to the intermembrane space.

NADH-enzyme Q reductase

The ________ complex also transports __ protons into the intermembrane space.

cytochrome c reductase, 4

The cytochrome c oxidase complex transports __ protons into the space.

In the last step of the ETS, __ is the final electron acceptor.

glucose
lactic acid
pyruvic acid
fructose 1,6-biphosphate

mitochondria matrix

acetyl-CoA
citric acid
oxaloacetic acid
succinic acid

inner mitochondrial membrane

ATP synthase
cytochrome C
flavin mononucleotide
proton pumps

Glycolysis is the metabolic pathway in which glucose is converted into two molecules of

In addition to pyruvate, glycolysis results in the production of two molecules of

Glycolysis releases energy, so it is ____________ .

When two hydrogen atoms are added to pyruvate, ____________ is produced.

In order for glycolysis to continue, there must be adequate amounts of ____________ available, which is produced in the lactic acid pathway.

The lactic acid pathway is a type of ____________ .

anaerboic metabolism

The formation of glucose from amino acids is called ____________ .

gluconeogenesis

The process by which amino acids are converted to urea is called ____________ .

oxidative deamination

More importantly, all organs must use ____________ primarily for energy.

After anaerobic exercise, lactic acid is converted to pyruvic acid, which enters the ____________ pathway and can be used for energy.

The main substrates for gluconeogenesis are the three-carbon-long molecules of alanine, glycerol, and ____________ .

Keto acids can be converted to amino acids by the process of

facilitated diffusion

Includes the movement of small organic molecules through a protein located within the plasma membrane

simple diffusion

Involves the movement of lipid soluble molecules from a high concentration to a low concentration

Which of the following is true of catalysts?

they lower the activation energy of a reaction

Each NAD can accept _____ electron(s) and ______ proton(s), so the reduced form is _________.

2, 1, NADH + H+

Blood sugar refers to what molecule circulating in blood?

NAD and FAD are important coenzymes that act as hydrogen carriers

What does FADH2 and NADH bring to the electron transport chain?

high energy electrons

One turn of _____________ produces 1 FADH2, 1 ATP, and 3 NAD

citric acid cycle

What is the final product of the electron transport chain?

As high energy electrons pass down the electron transport chain, what occurs?

H+ is pumped inside

The proton & electron carrier that gets oxidized and reduced in the citric acid cycle is

Glycolysis releases how many hydrogen molecules?

Aerobic cellular respiration ________.

generates water

What theory explains the ability of the electron transport system to pump protons between the inner and outer mitochondrial membranes?

chemiosmotic thory

breakdown of glucose for energy

formation of fat

formation of glycogen from glucose

formation of acetyl CoA from fatty acids

lactic acid fermentation

conversion of glucose to pyruvic acid then lactic acid because oxygen isn't available

In the breakdown of a molecule of glucose in the cytoplasm, a total of________ molecules of ATP are produced, but ____ molecules are spent initially to get the process started.

Proteins that act as 'glue' bewteen cells and the extracellular matrix are

integrin proteins

The two main classes of hormones are:amine/peptide and steroid hormones

amine/peptide and steroid hormones

Which type of local chemical signaling system sends molecules from signaling cell to nearby target cell?

paracrine signaling

What type of cell signaling occurs through the extracellular matrix to nearby target cells?

paracrine signaling

Movement of large molecules into a cell is called ________.

endocytosis/ bulk transport

Diffusion ________ the entropy of a solution.

Which of the following is a function of the steep Na+/K+ gradient across the cell membrane?

Provides energy for coupled transport
Creates electrochemical gradient
Maintains osmotic pressure

Active transport ________.

goes against the concentration gradient

second messengers...

-are small intracellular molecules that participate in signal transduction
-amplify the effects of the signal
-are removed in order to terminate a cellular signaling response
-play a role in activation of intracellular signal transduction

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