Question 1

What conclusion can be drawn concerning an inhibitor if the Vmax is the same in the presence and absence of the inhibitor?

Accepted Answer

A)   The inhibitor binds to the substrate.
B)   The inhibitor can be overcome with sufficiently high concentrations of substrate.
C)   The inhibitor reacts with a critical residue of the enzyme.
D)   The inhibitor binds to the same active site as the substrate.
E)   The KM is smaller in the presence of inhibitor.

Question 2

The Circe effect enhances what aspect of enzyme catalysis?

Accepted Answer

A)   catalysis of substrate to product
B)   binding of substrate
C)   removal of product(s)  from active site
D)   prevention of enzyme inhibition
E)   None of the answers is correct.

Question 3

The kcat is often referred to as the _____.

Accepted Answer

A)   turnover number
B)   Michaelis constant
C)   dissociation constant
D)   rate constant
E)   None of the answers is correct.

Question 4

Give an example of a reaction catalyzed by a hydrolase.

Accepted Answer

Hydrolases catalyze a reaction where a w...

Question 5

There are six basic categories of enzymes. List the categories, and define the type of reaction.

Accepted Answer

The categories include oxidoreductases (...

Question 6

What term describes an enzyme without its required cofactor?

Accepted Answer

A)   holoenzyme
B)   coenzyme
C)   isozyme
D)   apoenzyme
E)   None of the answers is correct. D

Question 7

In this type of inhibition, the inhibitor can only bind to the ES complex to form an ESI complex.

Accepted Answer

A)   competitive
B)   noncompetitive
C)   mixed
D)   uncompetitive
E)   None of the answers is correct.

Question 8

Compounds that resemble the transition state of a catalyzed reaction and inhibit enzyme activity are called ____________________________.

Accepted Answer

transition...

Question 9

In many enzyme assays, the natural substrate and product are not used. Why?

Accepted Answer

Many products are difficult to measure a...

Question 10

Explain what an abzyme is and give an example.

Accepted Answer

Catalytic antibodies are abzymes and are...

Question 11

A(n)  _____ requires an input of energy to proceed.

Accepted Answer

A)   reaction at equilibrium
B)   irreversible reaction
C)   spontaneous reaction
D)   exergonic reaction
E)   endergonic reaction

Question 12

Five KM values are given for the binding of substrates to a particular enzyme. Which has the strongest affinity when k   1 is greater than k2?

Accepted Answer

A)   150 mM
B)   0.15 mM
C)   150  μ\muμ M
D)   1.5 nM
E)   15000 pM

Question 13

If a reaction is exergonic at specific reactant concentrations, it is considered _____.

Accepted Answer

A)   at equilibrium
B)   nonspontaneous
C)   spontaneous
D)   irreversible
E)   None of the answers is correct.

Question 14

What is the common strategy by which catalysis occurs?

Accepted Answer

A)   increasing the probability of product formation
B)   shifting the reaction equilibrium
C)   stabilization of transition state
D)   All of the answers are correct.
E)   None of the answers is correct.

Question 15

Most known enzymes are proteins; however, some ___________ molecules have been shown to possess catalytic activity.

Accepted Answer

The answer of Most known enzymes are proteins; however, some...

Question 16

The difference between the standard-state free energy, ΔGº, and the biochemical standard-state free energy is that ΔGº′ refers to the standard free-energy change at ________.

Accepted Answer

pH 7

Question 17

What is an affinity label?

Accepted Answer

This is a substrate analog that is structurally similar to the substrate, binds to the active site, and chemically reacts with a residue in the active site. It is used to study enzyme structure and mechanism.

Question 18

You believe a substrate fits rigidly into a cleft like a key into a lock, but your roommate believes that the structure of the enzyme adapts to the substrate. Who is right?

Accepted Answer

You are both partially correct. Like a l...

Question 19

What term is used to describe the dynamic recognition of the substrate when binding to an enzyme occurs?

Accepted Answer

A)   allosteric modulation
B)   transition state enhancement
C)   sequential binding
D)   induced fit
E)   None of the answers is correct.

Question 20

Which of the following is true under the following conditions: the enzyme concentration is 5 nM, the substrate concentration is 5 mM, and the KM is 5  μ\muμ 0M?

Accepted Answer

A)   The enzyme is saturated with substrate.
B)   Most of the enzyme does not have substrate bound.
C)   There is more enzyme than substrate.
D)   All of the answers are correct.
E)   None of the answers is correct.

Exam 8: Enzymes: Basic Concepts and Kinetics

What conclusion can be drawn concerning an inhibitor if the Vmax is the same in the presence and absence of the inhibitor?

Correct AnswerverifiedShow Answer

The Circe effect enhances what aspect of enzyme catalysis?

Correct AnswerverifiedShow Answer

The kcat is often referred to as the _____.

Correct AnswerverifiedShow Answer

Give an example of a reaction catalyzed by a hydrolase.

Correct AnswerverifiedHydrolases catalyze a reaction where a w...View AnswerShow Answer

There are six basic categories of enzymes. List the categories, and define the type of reaction.

Correct AnswerverifiedThe categories include oxidoreductases (...View AnswerShow Answer

What term describes an enzyme without its required cofactor?

Correct AnswerverifiedD

In this type of inhibition, the inhibitor can only bind to the ES complex to form an ESI complex.

Correct AnswerverifiedShow Answer

Compounds that resemble the transition state of a catalyzed reaction and inhibit enzyme activity are called ____________________________.

Correct Answerverifiedtransition...View AnswerShow Answer

In many enzyme assays, the natural substrate and product are not used. Why?

Correct AnswerverifiedMany products are difficult to measure a...View AnswerShow Answer

Explain what an abzyme is and give an example.

Correct AnswerverifiedCatalytic antibodies are abzymes and are...View AnswerShow Answer

A(n) _____ requires an input of energy to proceed.

Correct AnswerverifiedShow Answer

Five KM values are given for the binding of substrates to a particular enzyme. Which has the strongest affinity when k 1 is greater than k2?

Correct AnswerverifiedShow Answer

If a reaction is exergonic at specific reactant concentrations, it is considered _____.

Correct AnswerverifiedShow Answer

What is the common strategy by which catalysis occurs?

Correct AnswerverifiedShow Answer

Most known enzymes are proteins; however, some ___________ molecules have been shown to possess catalytic activity.

Correct AnswerverifiedShow Answer

The difference between the standard-state free energy, ΔGº, and the biochemical standard-state free energy is that ΔGº′ refers to the standard free-energy change at ________.

Correct AnswerverifiedpH 7

What is an affinity label?

Correct AnswerverifiedThis is a substrate analog that is structurally similar to the substrate, binds to the active site, and chemically reacts with a residue in the active site. It is used to study enzyme structure and mechanism.

You believe a substrate fits rigidly into a cleft like a key into a lock, but your roommate believes that the structure of the enzyme adapts to the substrate. Who is right?

Correct AnswerverifiedYou are both partially correct. Like a l...View AnswerShow Answer

What term is used to describe the dynamic recognition of the substrate when binding to an enzyme occurs?

Correct AnswerverifiedShow Answer

Which of the following is true under the following conditions: the enzyme concentration is 5 nM, the substrate concentration is 5 mM, and the KM is 5 μ\muμ 0M?

Correct AnswerverifiedShow Answer

What conclusion can be drawn concerning an inhibitor if the V_max is the same in the presence and absence of the inhibitor?

Correct Answer
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The k_cat is often referred to as the _____.

Correct Answer
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Hydrolases catalyze a reaction where a w...
View Answer

Correct Answer
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The categories include oxidoreductases (...
View Answer

Correct Answer
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D

Correct Answer
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transition...
View Answer

Correct Answer
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Many products are difficult to measure a...
View Answer

Correct Answer
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Catalytic antibodies are abzymes and are...
View Answer

Correct Answer
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Five K_M values are given for the binding of substrates to a particular enzyme. Which has the strongest affinity when k ₁ is greater than k₂?

Correct Answer
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pH 7

Correct Answer
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This is a substrate analog that is structurally similar to the substrate, binds to the active site, and chemically reacts with a residue in the active site. It is used to study enzyme structure and mechanism.

Correct Answer
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You are both partially correct. Like a l...
View Answer

Correct Answer
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Which of the following is true under the following conditions: the enzyme concentration is 5 nM, the substrate concentration is 5 mM, and the K_M is 5 $\mu$ 0M?

Correct Answer
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