Question 1

Which of the following best describes the role of an enzyme in a chemical reaction?

Accepted Answer

It lowers the activation energy $$\Delta G$$^{\ddagger}$$, thereby increasing the reaction rate.

Question 2

Which property distinguishes enzymes from most chemical catalysts used in organic chemistry labs?

Accepted Answer

Enzymes exhibit both stereospecificity and regiospecificity under mild conditions.

Question 3

Consider the reaction coordinate diagram for an enzyme-catalyzed reaction. What does the difference between $$\Delta G$$^{\ddagger}$$_{uncat}$$ and $$\Delta G$$^{\ddagger}$$_{cat}$$ represent?

Accepted Answer

The amount by which the enzyme lowers the activation energy barrier.

Question 4

Which of the following is NOT a strategy enzymes use to accelerate reactions?

Accepted Answer

Increasing the temperature of the reaction environment.

Question 5

A patient has a genetic mutation that affects the active site of an enzyme, reducing its ability to bind the transition state. What is the most likely consequence?

Accepted Answer

The reaction rate will decrease due to a higher $$\Delta G$$^{\ddagger}$$.

Question 6

Which of the following best explains why enzymes can couple unfavorable reactions to favorable ones?

Accepted Answer

Enzymes physically link the reactions, allowing the free energy from a favorable reaction to drive an unfavorable one.

Question 7

Which statement about the transition state in enzyme-catalyzed reactions is correct?

Accepted Answer

Enzymes stabilize the transition state, lowering the activation energy required for the reaction.

Question 8

Which of the following is a direct consequence of enzyme stereospecificity?

Accepted Answer

Enzymes produce only one enantiomer or stereoisomer of a product.

Question 9

In the reaction catalyzed by hexokinase, ATP and glucose are converted to ADP and glucose-6-phosphate. Why is this reaction possible in cells?

Accepted Answer

Hexokinase couples the unfavorable phosphorylation of glucose to the favorable hydrolysis of ATP.

Question 10

Which of the following terms refers to the non-protein component required for enzyme activity?

Accepted Answer

Cofactor

Question 11

Which equation describes the rate constant $$k$$ for a reaction according to transition state theory?

Accepted Answer

$$k = \frac{k_B T}{h} e$$^{-\Delta G^{\ddagger}$$/RT}$$

Question 12

Which of the following is true regarding the effect of enzymes on reaction equilibrium?

Accepted Answer

Enzymes do not affect the equilibrium position; they only affect the rate.

Question 13

Which of the following best describes the concept of entropy reduction in enzyme catalysis?

Accepted Answer

Enzymes bring substrates together in the correct orientation, reducing the entropy cost of the reaction.

Question 14

A drug inhibits an enzyme by binding to its active site and preventing substrate binding. What type of inhibition is this?

Accepted Answer

Competitive inhibition

Question 15

Which of the following is a correct statement about the enzyme-substrate complex?

Accepted Answer

It is a transient complex formed when the substrate binds to the enzyme's active site.

Question 16

Which of the following is NOT a reason why studying enzyme function is important?

Accepted Answer

Enzymes are always consumed in reactions and must be replaced.

Question 17

Which of the following best describes the difference between an apoenzyme and a holoenzyme?

Accepted Answer

A holoenzyme is the complete, active enzyme with its cofactor or coenzyme bound.

Question 18

Which of the following is a key feature of enzyme catalysis that helps minimize unwanted side reactions?

Accepted Answer

Enzymes are highly specific for their substrates and reaction pathways.

Question 19

Which of the following statements about enzyme regulation is correct?

Accepted Answer

Enzymes can be regulated by factors such as phosphorylation, allosteric effectors, and changes in pH.

Introduction to Enzymes: Properties, Mechanisms, and Biological Relevance

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드