Deck 3: Cellular Structure, Proteins, and Metabolism

Question 1

In the fluid-mosaic model of membrane structure,

A)The proteins exist in a bilayer formation
B)The phospholipids are tightly bound in place
C)The term "mosaic" refers to the cholesterol component
D)Integral proteins are amphipathic
E)None of the choices are true

Answer 1

D

Question 2

A gene

A)Contains information necessary for the synthesis of proteins
B)Is a sequence of nucleotides in DNA
C)Is composed of many molecules of DNA
D)Contains information necessary for the synthesis of proteins and is a sequence of nucleotides in DNA
E)All of the choices are correct

Answer 2

D

Question 3

Cell A is a gland cell that makes and secretes proteins.Cell B is another type of cell that synthesizes and secretes steroids.If you were to look at electron micrographs of the two cells,what differences would you expect to see?

A)Cell A would have more granular endoplasmic reticulum than cell B
B)Cell A would have fewer secretion granules than cell B
C)Cell A would have more agranular endoplasmic reticulum than cell B
D)Both cell A would have more granular endoplasmic reticulum than cell B and cell A would have fewer secretion granules than cell B are correct
E)Both cell A would have more granular endoplasmic reticulum than cell B and cell A would have more agranular endoplasmic reticulum than cell B are correct

Answer 3

A

Question 4

Which of the following is not true regarding cell membrane junctions?

A)Tight junctions anchor cells to basement membranes in tissues that are subjected to stretch
B)Desmosomes anchor adjacent cells together
C)Gap junctions seal spaces between cells and control permeability across epithelial membranes
D)Both tight junctions anchor cells to basement membranes in tissues that are subjected to stretch and desmosomes anchor adjacent cells together are correct
E)Both tight junctions anchor cells to basement membranes in tissues that are subjected to stretch and gap junctions seal spaces between cells and control permeability across epithelial membranes are correct

Question 5

Neurons have a very prominent nucleolus which indicates that they are actively

A)Making ATP
B)Synthesizing lipids
C)Manufacturing ribosomes
D)Breaking down carbohydrates
E)Dividing by mitosis

Question 6

Cholesterol

A)Is slightly amphipathic
B)Is a prominent lipid component of all membranes in a cell
C)Allows the plasma membrane to form vesicles that deliver their contents to cell organelles
D)Both is slightly amphipathic and is a prominent lipid component of all membranes in a cell are correct
E)Both is slightly amphipathic and allows the plasma membrane to form vesicles that deliver their contents to cell organelles are correct

Question 7

Which organelles would you expect to be especially numerous in cells that expend a great deal of energy in the form of ATP?

A)Peroxisomes
B)Endosomes
C)Lysosomes
D)Ribosomes
E)Mitochondria

Question 8

Cell membranes

A)Are components of the cytosol
B)Are passive barriers against the passage of molecules from one side to the other
C)Consist primarily of protein and carbohydrate
D)Consist primarily of phospholipids and protein
E)Both are passive barriers against the passage of molecules from one side to the other and consist primarily of protein and carbohydrate are correct

Question 9

Functions of agranular endoplasmic reticulum include

A)Synthesis of proteins for use in the cell
B)Synthesis of steroids
C)Storage of intracellular calcium ion
D)Synthesis of proteins for use in the cell and storage of intracellular calcium ion
E)Synthesis of steroids and storage of intracellular calcium ion

Question 10

Functions of the Golgi apparatus include

A)Modifying proteins synthesized on free ribosomes
B)Modifying proteins synthesized on ribosomes associated with granular endoplasmic reticulum
C)Allowing the distribution of modified proteins throughout the cell in vesicles
D)Modifying proteins synthesized on free ribosomes and allowing the distribution of modified proteins throughout the cell in vesicles
E)Modifying proteins synthesized on ribosomes associated with granular endoplasmic reticulum and allowing the distribution of modified proteins throughout the cell in vesicles

Question 11

Desmosomes represent a type of cell to cell connection resembling a rivet

A)Well suited to locations in the body where considerable stresses due to stretching are likely to occur
B)Which is enhanced by proteins that extend from the cell into the extracellular space
C)That can be strengthened by keratin filaments that extend to interior cell structures
D)Both well suited to locations in the body where considerable stresses due to stretching are likely to occur and which is enhanced by proteins that extend from the cell into the extracellular space are correct
E)All of these choices are correct

Question 12

Carbohydrate chains can be added to glycoproteins by the

A)Golgi apparatus
B)Smooth endoplasmic reticulum
C)Nucleus
D)Lysosomes
E)Mitochondria

Question 13

In Tay Sach's disease,lysosomes do not carry out their normal function.Predict which condition would be a symptom of Tay Sach's disease.

A)There is excessive accumulation of damaged organelles in a cell
B)Cells are unable to synthesize proteins
C)Cells can only make ATP by glycolysis
D)Proteins cannot be secreted by exocytosis
E)Steroid hormones can't be produced

Question 14

In contrast to "spot type" cell junctions,_____ junctions resemble tightly drawn belts,completely encircling the cell and leaving gaps above below them at the points of attachment with adjacent cells.

A)Cadherin
B)Tight
C)Gap
D)Connexin
E)Nexus

Question 15

Since their discovery,vaults appear to be associated with pores in the nuclear membrane

A)And may have an ability to influence the effectiveness of anticancer drugs
B)And could be used as a treatment for viral infections
C)Consequently representing a point of potential vulnerability to cells infected by bacteria
D)Clearly representing an organelle with functions that are similar if not identical to mitochondria
E)That participate in the process of mitotic cell division

Question 16

Tight junctions

A)Hold cells tightly together so that they cannot readily be pulled apart
B)Form barriers that regulate the passage of materials across epithelial membranes
C)Are commonly found in smooth muscle
D)Both hold cells tightly together so that they cannot readily be pulled apart and form barriers that regulate the passage of materials across epithelial membranes are correct
E)Both form barriers that regulate the passage of materials across epithelial membranes and are commonly found in smooth muscle are correct

Question 17

A major function of plasma membranes is to

A)Store calcium ions
B)Store organic chemicals for metabolism
C)Provide genetic information
D)Generate ATP
E)Regulate the passage of molecules into and out of the cell

Question 18

Phospholipids form effective barriers between the aqueous cytosol of cells and the aqueous extracellular fluid because they are

A)Polar
B)Nonpolar
C)Lipids
D)Rigid
E)Amphipathic

Question 19

The organelles that digest engulfed bacteria and cell debris are the

A)Peroxisomes
B)Endosomes
C)Lysosomes
D)Ribosomes
E)Mitochondria

Question 20

Which of the following is not true of the cytoskeleton?

A)It refers to the cellular components of bone
B)It refers to a network of cytoplasmic filaments
C)It is important for cellular movement
D)It helps to determine a cell's shape
E)None of the choices are false

Question 21

A binding site on a protein is

A)An area of the protein with a shape complementary to that of a ligand
B)Determined by the amino acid sequence of the protein
C)Formed by a region of amino acids that must be adjacent to each other on a polypeptide chain
D)An area of the protein with a shape complementary to that of a ligand and determined by the amino acid sequence of the protein
E)All of the choices are correct

Question 22

Functions of the Golgi apparatus include

A)Sorting of proteins destined for various destinations in the cell
B)Modifying proteins destined for secretion
C)Packaging enzymes destined for lysosomes
D)Sorting of proteins destined for various destinations in the cell and modifying proteins destined for secretion
E)All of the choices are correct

Question 23

A certain protein receptor is capable of binding the neurotransmitter epinephrine but does not bind to the neurotransmitters dopamine,glutamate or serotonin.This is because the receptor displays

A)Saturation
B)Inhibition
C)Specificity
D)Acclimatization
E)All of the choices are correct

Question 24

A competitive antagonist for a ligand

A)Does not interfere with the action of the ligand
B)Blocks the binding of the ligand to its binding site and prevents activation of the protein
C)Causes covalent modulation of the ligand, usually by phosphorylation or dephosphorylation
D)Both blocks the binding of the ligand to its binding site and prevents activation of the protein and causes covalent modulation of the ligand, usually by phosphorylation or dephosphorylation are correct
E)None of the choices are correct

Question 25

The genetic code

A)Consists of one code word for each amino acid
B)Is the same for all cells
C)Is the same for all organisms
D)Is the same for all cells and is the same for all organisms
E)All of the choices are correct

Question 26

Allosteric proteins

A)Contain more than one kind of binding site
B)Undergo a change of shape when a ligand binds to the regulatory binding site
C)Are always activated when a modulator molecule binds to the regulatory site
D)Both contain more than one kind of binding site and undergo a change of shape when a ligand binds to the regulatory binding site are correct
E)All of the choices are correct

Question 27

During protein synthesis,

A)rRNA and ribosomal proteins are required to identify the beginning of the mRNA coding sequence
B)Ribosomal enzymes catalyze the formation of hydrogen bonds between amino acids
C)mRNA is used up during the formation of peptide bonds
D)Both rRNA and ribosomal proteins are required to identify the beginning of the mRNA coding sequence and ribosomal enzymes catalyze the formation of hydrogen bonds between amino acids occur
E)All of the choices take place

Question 28

A ligand is a molecule that binds to

A)A protein by covalent bonds
B)A protein by noncovalent bonds
C)Any other molecule by means of noncovalent bonds
D)A protein by noncovalent bonds and any other molecule by means of noncovalent bonds
E)None of the choices are correct

Question 29

RNA synthesis from a DNA template

A)Is called translation of the message
B)Requires DNA polymerase
C)Is regulated
D)Occurs in the nucleolus
E)None of the choices are correct

Question 30

A genome is

A)A cluster of genes that are all regulated in the same manner
B)A measure of the genetic variability in a population
C)A region of DNA that codes for a single protein
D)All of the DNA and RNA in a cell at a given point in time
E)The total genetic information in a typical cell of an organism

Question 31

The signal sequence of a protein is

A)The amino acid sequence of the binding site of the protein
B)The sequence that targets a protein for packaging in the granular endoplasmic reticulum
C)Usually cleaved in the Golgi apparatus
D)The amino acid sequence of the binding site of the protein and usually cleaved in the Golgi apparatus
E)The sequence that targets a protein for packaging in the granular endoplasmic reticulum and usually cleaved in the Golgi apparatus

Question 32

Which of the following does not describe the 50 percent saturation point of a solution of ligands and proteins?

A)It refers to the amount of protein required to bind 50 percent of the ligand
B)It refers to the amount of ligand required to bind 50 percent of the binding sites
C)It refers to the amount of ligand required to bind one binding site 50 percent of the time
D)It can be used to measure the affinity of a binding site for a ligand

Question 33

Which of the following statements about RNA transcription and translation is true?

A)All of the nucleotide sequences in a gene are transcribed into RNA
B)The entire transcribed message of a gene is translated into amino acid sequences
C)The mRNA that enters the cytosol is considerably shorter than that synthesized during transcription
D)Both all of the nucleotide sequences in a gene are transcribed into RNA and the mRNA that enters the cytosol is considerably shorter than that synthesized during transcription are correct
E)All of the choices are correct

Question 34

Transfer RNA

A)Functions to transport mRNA out of the nucleus
B)Binds specifically to mRNA and nonspecifically to amino acids
C)Binds specifically to amino acids and nonspecifically to mRNA
D)Binds specifically to mRNA and to amino acids
E)None of the choices are correct

Question 35

How does the synthesis of proteins that are destined to be secreted differ from that of proteins with functions inside the cell?

A)Proteins destined to be secreted have a signal sequence
B)Proteins destined to be secreted are synthesized on free ribosomes
C)Proteins destined to be secreted are packaged into secretory vesicles in the granular endoplasmic reticulum
D)Both proteins destined to be secreted have a signal sequence and proteins destined to be secreted are synthesized on free ribosomes are correct
E)Both proteins destined to be secreted have a signal sequence and proteins destined to be secreted are packaged into secretory vesicles in the granular endoplasmic reticulum are correct

Question 36

A codon is

A)A triplet of deoxyribonucleotides
B)A triplet of ribonucleotides
C)A sequence of ribonucleotides on tRNA
D)A triplet of ribonucleotides and a sequence of ribonucleotides on tRNA
E)None of the choices are correct

Question 37

The segments of primary RNA that are cleaved off by spliceosomes are called

A)Codons
B)Introns
C)Exons
D)Anticodons
E)None of the choices are correct

Question 38

The affinity a binding site has for a ligand

A)Can be influenced by the shape of the binding site
B)Can be influenced by the presence of charged groups on the ligand and the binding site
C)Is a measure of how readily a bound ligand can be released from the protein
D)Both can be influenced by the shape of the binding site and can be influenced by the presence of charged groups on the ligand and the binding site are correct
E)All of the choices are correct

Question 39

Which of the following does not affect the rate of synthesis of a protein in a cell?

A)The rate of its gene's transcription
B)The rate of initiating protein assembly on ribosomes
C)The rate of mRNA degradation
D)The presence or absence of transcription factors
E)The rate of its tRNA synthesis

Question 40

The codon that corresponds to the DNA sequence G-T-A is

A)G-T-A
B)A-T-G
C)C-A-T
D)C-A-U
E)T-A-C

Question 41

The term "allosteric modulation" refers to

A)Regulation of physiological functions by the sympathetic division of the autonomic nervous system
B)Modification of the functional state of a protein by temperature or pH
C)The change in the shape and functional state of a protein that occurs when a ligand binds to a receptor site
D)The fact that all of the receptors must be occupied to have a biological effect
E)All of the choices are correct

Question 42

Enzymes

A)Are catalysts in chemical reactions
B)Can be carbohydrate molecules
C)Are broken down during chemical reactions they catalyze
D)Have names generally ending in the suffix "-ose."
E)Are described by all of the choices

Question 43

When a chemical binds noncovalently to a protein at a distance from its functional site and causes a conformational change in the site that prevents the natural ligand from binding,this is an example of

A)Allosteric modulation
B)Noncompetitive antagonism
C)Competitive modulation
D)Allosteric modulation and noncompetitive antagonism
E)None of the choices are correct

Question 44

Consider the reaction: M + N $\overrightarrow { \overleftarrow { }}$ Y + Z Which of the following is correct?

A)The reaction is reversible
B)At chemical equilibrium, increasing the concentration of M will drive the reaction to the left
C)At chemical equilibrium, decreasing the concentration of M will drive the reaction to the left
D)Both the reaction is reversible and at chemical equilibrium, increasing the concentration of M will drive the reaction to the left are correct
E)Both the reaction is reversible and at chemical equilibrium, decreasing the concentration of M will drive the reaction to the left are correct

Question 45

A cofactor may

A)Alter the conformation of an enzyme
B)Be a metal such as iron
C)Be a substrate in a catalyzed reaction
D)Alter the conformation of an enzyme and be a metal such as iron
E)All of the choices are correct

Question 46

When a chemical reaction is at equilibrium

A)The rate of the reaction in one direction is equal to the rate in the reverse direction
B)The concentration of the reactants is equal to the concentration of the products
C)The ratio of reactants to products varies according to the amount of energy released in one direction
D)The rate of the reaction in one direction is equal to the rate in the reverse direction and the concentration of the reactants is equal to the concentration of the products occur
E)The rate of the reaction in one direction is equal to the rate in the reverse direction and the ratio of reactants to products varies according to the amount of energy released in one direction occur

Question 47

Which of the following statements concerning enzymes is true?

A)Enzymes increase the activation energy of a reaction
B)Enzymes will generally change the equilibrium concentrations of the products and reactants
C)Enzymes will generally decrease the time required to reach equilibrium
D)Both enzymes increase the activation energy of a reaction and enzymes will generally change the equilibrium concentrations of the products and reactants are correct
E)Both enzymes will generally change the equilibrium concentrations of the products and reactants and enzymes will generally decrease the time required to reach equilibrium are correct

Question 48

A catalyst for a chemical reaction

A)Lowers the activation energy of the reaction
B)Is modified by the reaction
C)Changes the energy content of the reactants
D)Both lowers the activation energy of the reaction and is modified by the reaction are correct
E)Both lowers the activation energy of the reaction and changes the energy content of the reactants are correct

Question 49

Phosphorylation or dephosphorylation of proteins is a common means of

A)Covalent modulation of the proteins
B)The activation or inactivation of kinases
C)Allosteric modulation of the proteins
D)Covalent modulation of the proteins and the activation or inactivation of kinases
E)All of the choices are correct

Question 50

Which of the following would be a possible effect of a dietary supplement that claims to increase metabolism?

A)It would increase the chemical breakdown of molecules in the body
B)It would increase the chemical synthesis of molecules in the body
C)It would increase the concentration of DNA in a cell
D)It would increase the energy released from a chemical reaction
E)Both it would increase the chemical breakdown of molecules in the body and it would increase the chemical synthesis of molecules in the body are correct

Question 51

With regard to chemical reaction rates,which of the following statements is true?

A)Increasing the concentration of the reactants will increase the reaction rate
B)Increasing the temperature will increase the reaction rate
C)Increasing the activation energy will increase the reaction rate
D)Both increasing the concentration of the reactants will increase the reaction rate and increasing the temperature will increase the reaction rate are correct
E)All of the choices are correct

Question 52

The probability of a reaction occurring is increased

A)By decreasing reactant concentrations
B)By increasing the activation energy
C)By increasing the product concentration
D)If the reaction uses a great deal of energy
E)By none of the choices

Question 53

In skeletal muscle,when calcium binds to the regulatory protein troponin,it increases the affinity of neighboring troponin molecules for calcium.This is an example of

A)Allosteric modulation
B)Cooperativity
C)Covalent modulation
D)Phosphorylation
E)Saturation

Question 54

Modulator molecules

A)Bind to proteins and cause a conformational change that facilitates or inhibits the binding of the functional ligand to its binding site
B)Enable ligands to bind to their binding sites by phosphorylating the ligand
C)Prevent ligands from binding to their binding sites by phosphorylating the ligand
D)Denature proteins containing binding sites for ligands
E)Do none of the choices

Question 55

Protein kinases

A)Add phosphate groups to proteins
B)Produce effects similar to allosteric modulation
C)Perform the opposite function as phosphatases
D)Use ATP to carry out their reactions
E)Do all of the choices

Question 56

A coenzyme

A)Is an organic cofactor
B)May be a metal such as iron
C)Is a substrate for a catalyzed reaction
D)Both is an organic cofactor and is a substrate for a catalyzed reaction
E)Both may be a metal such as iron and is a substrate for a catalyzed reaction

Question 57

Consider the reaction: H₂CO₃ $\rightarrow$ CO₂ + H₂O + 4 kcal/mol Which of the following statements is true?

A)The reaction is anabolic
B)The reaction is catabolic
C)The energy content of the reactants is greater than the energy content of the products
D)Both the reaction is anabolic and the energy content of the reactants is greater than the energy content of the products are correct
E)Both the reaction is catabolic and the energy content of the reactants is greater than the energy content of the products are correct

Question 58

A chemical catalyst increases the rate of a reaction by

A)Acting as one of the reactant molecules
B)Decreasing the energy of activation
C)Increasing the energy content of the product molecules
D)Increasing the temperature of a solution
E)All of the choices are correct

Question 59

The term "metabolism"

A)Refers to all the chemical reactions that occur in the body
B)Includes the synthesis of complex molecules from simpler molecules
C)Includes the breakdown of complex molecules into simpler molecules
D)Includes anabolism and catabolism
E)Is described by all of the choices

Question 60

At equilibrium,in an irreversible reaction

A)Almost all of the reactants will have been converted to products
B)There will be an equal number of products and reactants
C)There will be very few molecules of product
D)Small amounts of energy will have been released
E)There will be an equal number of products and reactants and small amounts of energy will have been released will occur

Question 61

Which of the following statements concerning energy storage in the body is true?

A)Most is stored in the form of ATP
B)Most is stored in the form of glucose
C)Most is stored in the form of fat
D)Most is stored in the form of protein
E)Most is stored in the form of DNA

Question 62

Which of the following metabolic pathways does not require oxygen?

A)Glycolysis
B)Oxidative phosphorylation
C)Krebs cycle
D)The breakdown of fatty acids to CO₂ and H₂O
E)None of the choices are correct

Question 63

Glucose

A)Is the only carbohydrate utilized as an energy source
B)Must be phosphorylated before it can be metabolized
C)Can be synthesized from other types of molecules, including amino acids and triacylglycerol
D)Both is the only carbohydrate utilized as an energy source and must be phosphorylated before it can be metabolized are correct
E)Both must be phosphorylated before it can be metabolized and can be synthesized from other types of molecules, including amino acids and triacylglycerol are correct

Question 64

Fatty acid catabolism

A)Takes place in the cytosol of cells
B)Is initiated by the binding of a molecule of coenzyme A
C)Proceeds by a process called beta-oxidation
D)Generates one molecule of acetyl coenzyme A for every carbon atom in the fatty acid
E)Both is initiated by the binding of a molecule of coenzyme A and proceeds by a process called beta-oxidation are correct

Question 65

When glucose is catabolized in the absence of oxygen,

A)Pyruvate formed in glycolysis will generally be converted to lactate
B)Pyruvate formed in glycolysis will generally be converted to acetyl coenzyme A, which will enter the Krebs cycle
C)The number of ATP molecules formed per molecule of glucose will be less than the number formed in the presence of oxygen
D)Both pyruvate formed in glycolysis will generally be converted to lactate and the number of ATP molecules formed per molecule of glucose will be less than the number formed in the presence of oxygen will occur
E)Both pyruvate formed in glycolysis will generally be converted to acetyl coenzyme A, which will enter the Krebs cycle and the number of ATP molecules formed per molecule of glucose will be less than the number formed in the presence of oxygen will occur

Question 66

ATP is

A)Formed during the hydrolysis of ADP
B)Used by cells for the storage of energy
C)Used to transfer energy within a cell
D)A protein
E)Both used by cells for the storage of energy and used to transfer energy within a cell

Question 67

Which of the following statements concerning complete oxidation of glucose is true?

A)Carbon dioxide is not released
B)Oxygen is released
C)Oxygen is used during the Krebs cycle reactions
D)Carbon dioxide is released during the Krebs cycle reactions
E)None of the choices are true

Question 68

Oxidative phosphorylation

A)Requires the presence of unoccupied coenzymes
B)Requires phosphorylated organic molecules
C)Produces the great majority of useable energy for cell functions
D)Both requires the presence of unoccupied coenzymes and produces the great majority of useable energy for cell functions are correct
E)Both requires phosphorylated organic molecules and produces the great majority of useable energy for cell functions are correct

Question 69

Glycolysis

A)Does not occur in the absence of O₂
B)Does not occur in the presence of O₂
C)May result in the formation of two molecules of lactate for each molecule of glucose
D)Both does not occur in the absence of O₂ and may result in the formation of two molecules of lactate for each molecule of glucose are correct
E)Both does not occur in the presence of O₂ and may result in the formation of two molecules of lactate for each molecule of glucose are correct

Question 70

Which of the following is a way that the activity of an enzyme can be modified?

A)Allosteric activation
B)Allosteric inhibition
C)Covalent activation (e.g., by phosphorylation)
D)Covalent inhibition (e.g., by phosphorylation)
E)All of the choices are correct

Question 71

Fatty acid synthesis

A)Takes place in the cytosol of cells
B)Results in molecules with an even number of carbon atoms only
C)Requires more energy than is produced by the catabolism of the same fatty acid
D)Both takes place in the cytosol of cells and results in molecules with an even number of carbon atoms only are correct
E)All of the choices are correct

Question 72

Glycolysis

A)Yields two molecules of ATP for each molecule of glucose processed
B)May yield two molecules of lactate for each molecule of glucose processed
C)Takes place in the mitochondria of cells
D)Includes both yields two molecules of ATP for each molecule of glucose processed and may yield two molecules of lactate for each molecule of glucose processed
E)All of the choices are correct

Question 73

ATP is

A)A nucleotide
B)A lipid
C)An amino acid
D)A carbohydrate
E)A steroid

Question 74

In order to increase the overall rate of a metabolic pathway consisting of five reactions catalyzed by five different enzymes,which must occur?

A)Increasing the reaction rate of all five enzymes
B)Increasing the reaction rate of the fastest enzyme
C)Increasing the reaction rate of the slowest enzyme
D)Increasing the reaction rate of the first enzyme in the pathway
E)Increasing the reaction rate of the last enzyme in the pathway

Question 75

The reactions of the Krebs cycle

A)Take place in the cytosol of human cells
B)Generate ATP directly by substrate phosphorylation
C)Are important for the metabolism of carbohydrates but not other molecules
D)Both take place in the cytosol of human cells and generate ATP directly by substrate phosphorylation are correct
E)All of the choices are correct

Question 76

Which of the following is not a product of glycolysis?

A)Carbon dioxide
B)ATP
C)Pyruvate
D)NADH
E)All of the choices are products of glycolysis

Question 77

Which of the following is commonly used to regulate enzyme-mediated reactions in a cell?

A)Altering the enzyme concentration in the cell
B)Altering the enzyme's activity
C)Altering the cell's temperature
D)Both altering the enzyme concentration in the cell and altering the enzyme's activity are correct
E)All of the choices are correct

Question 78

Vitamins

A)May be precursors of coenzymes
B)May be synthesized by the body from precursor subunits
C)Are required in large amounts for metabolism
D)Both may be precursors of coenzymes and are required in large amounts for metabolism
E)All of the choices are correct

Question 79

The site where most of the ATP is generated in a cell is the

A)Nucleus
B)Plasma membrane
C)Endoplasmic reticulum
D)Golgi apparatus
E)Mitochondria

Question 80

Which of the following is true concerning the rate-limiting step in a metabolic pathway?

A)It is likely to be the slowest reaction in the pathway
B)It is likely to be the fastest reaction in the pathway
C)It may be subject to end-product inhibition
D)Both it is likely to be the slowest reaction in the pathway and it may be subject to end-product inhibition are correct
E)Both it is likely to be the fastest reaction in the pathway and it may be subject to end-product inhibition are correct