Question 1

Which of the following variables is part of the Michaelis-Menten equation?

Accepted Answer

A) kcat 
B) Km 
C) Vmax 
D) [S] 
E) v 
A) kcat 
B) Km 
C) Vmax 
D) [S] 
E) v A

Question 2

All of the following are associated with substration activation except

Accepted Answer

A) bond distortion. 
B) proton transfer. 
C) electron transfer. 
D) intramolecular hydrogen bonding. 
E) neutron transfer. 
A) bond distortion. 
B) proton transfer. 
C) electron transfer. 
D) intramolecular hydrogen bonding. 
E) neutron transfer. E

Question 3

An example of an irreversible inhibitor is

Accepted Answer

A) a competitive inhibitor. 
B) acetylcholinesterase. 
C) a noncompetitive inhibitor. 
D) penicillin. 
E) isoleucine. 
A) a competitive inhibitor. 
B) acetylcholinesterase. 
C) a noncompetitive inhibitor. 
D) penicillin. 
E) isoleucine. D

Question 4

An enzyme

Accepted Answer

A) decreases the rate of a reaction. 
B) binds substrates in a manner that facilitates the formation of product. 
C) changes the position of the equilibrium of the reaction. 
D) does not change the rate at which the equilibrium is achieved. 
E) is always a protein. 
A) decreases the rate of a reaction. 
B) binds substrates in a manner that facilitates the formation of product. 
C) changes the position of the equilibrium of the reaction. 
D) does not change the rate at which the equilibrium is achieved. 
E) is always a protein.

Question 5

________ inhibitors bind the enzyme at a location other than the active site but still interfere with product formation.

Accepted Answer

The answer of ________ inhibitors bind the enzyme at a...

Question 6

An enzyme is active in the stomach of an animal but quickly loses its activity when it leaves the stomach.This example illustrates that enzymes are

Accepted Answer

A) specific to the organs in which they are produced. 
B) inactivated by movement. 
C) sensitive to changes in pH. 
D) inactivated by inhibitors in the small intestine. 
E) consumed by the quantities of substrate in the small intestine. 
A) specific to the organs in which they are produced. 
B) inactivated by movement. 
C) sensitive to changes in pH. 
D) inactivated by inhibitors in the small intestine. 
E) consumed by the quantities of substrate in the small intestine.

Question 7

Which of the following best describes a metastable state?

Accepted Answer

A) This state is composed of the difference in activation energy of a catalyzed versus an uncatalyzed reaction. 
B) The metastable state is formed by transient complexes with the substrate. 
C) The metastable state is created by the prosthetic group of the enzyme. 
D) This state changes the position of the equilibrium but not the rate. 
E) The metastable state is a state of the substrate in which the reaction can proceed but typically requires a catalyst. 
A) This state is composed of the difference in activation energy of a catalyzed versus an uncatalyzed reaction. 
B) The metastable state is formed by transient complexes with the substrate. 
C) The metastable state is created by the prosthetic group of the enzyme. 
D) This state changes the position of the equilibrium but not the rate. 
E) The metastable state is a state of the substrate in which the reaction can proceed but typically requires a catalyst.

Question 8

Inhibitors of enzymes can be either reversible or irreversible.The most common reversible inhibitors are competitive or noncompetitive.Based on what you know about enzyme inhibitors,can you determine the type of inhibition discussed in these examples?
a.Diisopropyl fluorophosphate binds to acetylcholinesterase and permanently inactivates the enzyme.Paralysis results.
b.An inhibitor binds to the active site of an enzyme but disassociates and leaves the enzyme active.
c.A toxin binds to an enzyme.The enzyme then binds the substrate.No product is produced.The toxin may disassociate and allow for product formation.
d.Vitamin K is a coenzyme involved in blood clotting.An anticoagulant drug binds at the site of vitamin K and prevents clotting.Clotting resumes after the drug has been discontinued.
e.Aspirin binds to prostaglandin synthetase and permanently stops its ability to produce prostaglandin.

Accepted Answer

a.irreversible
b.com

Question 9

A noncompetitive inhibitor will

Accepted Answer

A) bind to free enzyme. 
B) bind to free product. 
C) decrease Vmax. 
D) decrease Km. 
E) both choices A and C 
A) bind to free enzyme. 
B) bind to free product. 
C) decrease Vmax. 
D) decrease Km. 
E) both choices A and C

Question 10

Saturation can be defined as

Accepted Answer

A) denaturation of an enzyme. 
B) the inability to increase reaction velocity beyond a finite upper limit. 
C) inhibition of enzyme function by blocking the active site. 
D) the substrate concentration at which velocity reaches one-half maximum velocity. 
E) a characteristic of all uncatalyzed reactions. 
A) denaturation of an enzyme. 
B) the inability to increase reaction velocity beyond a finite upper limit. 
C) inhibition of enzyme function by blocking the active site. 
D) the substrate concentration at which velocity reaches one-half maximum velocity. 
E) a characteristic of all uncatalyzed reactions.

Question 11

Covalent modification

Accepted Answer

A) can activate an enzyme. 
B) affects the activity of an enzyme by adding or removing a chemical group. 
C) can involve the addition of phosphate groups. 
D) produces modifications that can sometimes be reversed. 
E) all of the above 
A) can activate an enzyme. 
B) affects the activity of an enzyme by adding or removing a chemical group. 
C) can involve the addition of phosphate groups. 
D) produces modifications that can sometimes be reversed. 
E) all of the above

Question 12

Two specific coenzymes we need to obtain from our diet are niacin and ________,as our bodies cannot synthesize them.

Accepted Answer

The answer of Two specific coenzymes we need to obtain...

Question 13

Which of the following does accurately describe the Lineweaver-Burk plot?

Accepted Answer

A) It is a double-reciprocal plot. 
B) The y intercept is equal to 1/Vmax. 
C) The x intercept is -1/Km. 
D) It is a linear plot. 
E) Its slope is the same as the Eadie-Hofstee plot. 
A) It is a double-reciprocal plot. 
B) The y intercept is equal to 1/Vmax. 
C) The x intercept is -1/Km. 
D) It is a linear plot. 
E) Its slope is the same as the Eadie-Hofstee plot.

Question 14

All of the following are examples of irreversible enzyme inhibitors except

Accepted Answer

A) herbicides. 
B) pesticides. 
C) monoamine oxidase inhibitors. 
D) aspirin. 
E) natural poisons. 
A) herbicides. 
B) pesticides. 
C) monoamine oxidase inhibitors. 
D) aspirin. 
E) natural poisons.

Question 15

________ is a mechanism of lowering the activation energy barrier in some reactions,as with the detoxification of hydrogen peroxide.

Accepted Answer

Quantum tu

Question 16

A competitive inhibitor

Accepted Answer

A) binds at a site other than the active site. 
B) irreversibly binds and inactivates the enzyme. 
C) cannot be processed by the enzyme. 
D) does not inhibit enzyme activity but does lower substrate concentration. 
E) binds to and inactivates the substrate. 
A) binds at a site other than the active site. 
B) irreversibly binds and inactivates the enzyme. 
C) cannot be processed by the enzyme. 
D) does not inhibit enzyme activity but does lower substrate concentration. 
E) binds to and inactivates the substrate.

Question 17

A sick person often has a fever,which can inhibit the growth of bacteria because

Accepted Answer

A) bacteria reproduce more rapidly at higher body temperature. 
B) enzymes do not function as well at temperatures other than the optimal temperature. 
C) the higher temperature increases the activity of lyases. 
D) sweating removes prosthetic groups from biological enzymes. 
E) fever blocks synthesis of proteins in the bacterial nucleus. 
A) bacteria reproduce more rapidly at higher body temperature. 
B) enzymes do not function as well at temperatures other than the optimal temperature. 
C) the higher temperature increases the activity of lyases. 
D) sweating removes prosthetic groups from biological enzymes. 
E) fever blocks synthesis of proteins in the bacterial nucleus.

Question 18

Of the following,which is used to inhibit specific enzymes in the treatment of many bacterial and viral diseases?

Accepted Answer

A) substrate analogues 
B) noncompetitive inhibitors 
C) intercalating agents 
D) nitrous oxide 
E) X-rays 
A) substrate analogues 
B) noncompetitive inhibitors 
C) intercalating agents 
D) nitrous oxide 
E) X-rays

Question 19

The equation A-PO₄ + B → A + B-PO₄ would be catalyzed by which of the following classes of enzymes?

Accepted Answer

A) transferases 
B) oxidoreductases 
C) hydrolases 
D) ligases 
E) isomerases 
A) transferases 
B) oxidoreductases 
C) hydrolases 
D) ligases 
E) isomerases

Question 20

Which of the following is not true of the enzyme-substrate interaction?

Accepted Answer

A) Many enzymes are extremely specific regarding a substrate. 
B) Many enzymes cannot recognize a stereoisomer of their substrate. 
C) Some enzymes accept any of a whole group of substrates. 
D) Carboxypeptidase recognizes any of the amino acids from the carboxyl end of a polypeptide. 
E) Cells are often able to carry out metabolic activity with only a handful of enzymes. 
A) Many enzymes are extremely specific regarding a substrate. 
B) Many enzymes cannot recognize a stereoisomer of their substrate. 
C) Some enzymes accept any of a whole group of substrates. 
D) Carboxypeptidase recognizes any of the amino acids from the carboxyl end of a polypeptide. 
E) Cells are often able to carry out metabolic activity with only a handful of enzymes.

Exam 6: Enzymes: the Catalysts of Life

Which of the following variables is part of the Michaelis-Menten equation?

All of the following are associated with substration activation except

An example of an irreversible inhibitor is

An enzyme

________ inhibitors bind the enzyme at a location other than the active site but still interfere with product formation.

An enzyme is active in the stomach of an animal but quickly loses its activity when it leaves the stomach.This example illustrates that enzymes are

Which of the following best describes a metastable state?

A noncompetitive inhibitor will

Saturation can be defined as

Covalent modification

Two specific coenzymes we need to obtain from our diet are niacin and ________,as our bodies cannot synthesize them.

Which of the following does accurately describe the Lineweaver-Burk plot?

All of the following are examples of irreversible enzyme inhibitors except

________ is a mechanism of lowering the activation energy barrier in some reactions,as with the detoxification of hydrogen peroxide.

A competitive inhibitor

A sick person often has a fever,which can inhibit the growth of bacteria because

Of the following,which is used to inhibit specific enzymes in the treatment of many bacterial and viral diseases?

The equation A-PO₄ + B → A + B-PO₄ would be catalyzed by which of the following classes of enzymes?

Which of the following is not true of the enzyme-substrate interaction?

A Preview of the Cell

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: the Flow of Energy in the Cell

Membranes: Their Structure, function, and Chemistry

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System and Peroxisomes

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Iimessengers and Receptors

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: DNA, chromosomes, and the Nucleus

The Cell Cycle, DNA Replication, and Mitosis

Sexual Reproduction, meiosis, and Genetic Recombination

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

The Regulation of Gene Expression

Cancer Cells

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