Question 1

Which statement best describes the difference between catabolism and anabolism in microbial metabolism?

Accepted Answer

Catabolism breaks down complex molecules to release energy, while anabolism uses energy to build complex molecules from simpler ones.

Question 2

Which of the following best explains why ATP is considered an intermediate between catabolism and anabolism?

Accepted Answer

ATP stores energy released from catabolic reactions and provides energy for anabolic reactions.

Question 3

A bacterium is exposed to a temperature above its optimal range. What is the most likely effect on its enzymes?

Accepted Answer

Enzymes will denature, losing their functional shape and activity.

Question 4

Which of the following is a correct description of a holoenzyme?

Accepted Answer

A holoenzyme is the complete, active enzyme consisting of an apoenzyme and its cofactor.

Question 5

Which of the following is an example of competitive inhibition in microbial metabolism?

Accepted Answer

Sulfanilamide competes with PABA for the active site of an enzyme involved in folic acid synthesis.

Question 6

Which factor does NOT directly influence enzymatic activity?

Accepted Answer

The color of the enzyme

Question 7

Which enzyme class catalyzes the transfer of functional groups from one molecule to another?

Accepted Answer

Transferase

Question 8

A patient is given a drug that acts as a noncompetitive inhibitor of a bacterial enzyme. What is the most likely mechanism of action?

Accepted Answer

The drug binds to an allosteric site, altering the enzyme's shape and reducing activity.

Question 9

Which of the following best describes the role of NAD+ in cellular metabolism?

Accepted Answer

NAD+ is a coenzyme that acts as an electron carrier in oxidation-reduction reactions.

Question 10

Which equation correctly represents the reduction of NAD+ during a redox reaction?

Accepted Answer

$$\mathrm{NAD^+} + 2\mathrm{H} \rightarrow \mathrm{NADH} + \mathrm{H^+}$$

Question 11

Which of the following statements about metabolic pathways is TRUE?

Accepted Answer

Metabolic pathways are determined by enzymes, which are encoded by genes.

Question 12

A scientist observes that an enzyme catalyzes a reaction at a rate 10,000 times faster than the uncatalyzed reaction. What property of enzymes does this illustrate?

Accepted Answer

Enzymes lower the activation energy of reactions.

Question 13

Which of the following is NOT a component of a holoenzyme?

Accepted Answer

Substrate

Question 14

Which process is responsible for the breakdown of glucose to release energy in microbial cells?

Accepted Answer

Catabolism

Question 15

Which of the following is a real-life example of competitive inhibition used in medicine?

Accepted Answer

Sulfanilamide inhibits bacterial folic acid synthesis by competing with PABA.

Question 16

Which of the following best describes the effect of substrate concentration on enzyme activity?

Accepted Answer

Enzyme activity increases with substrate concentration until the enzyme becomes saturated.

Question 17

Which enzyme class is responsible for joining two molecules together using ATP?

Accepted Answer

Ligase

Question 18

A mutation in a gene encoding an enzyme's active site most likely affects which property?

Accepted Answer

The enzyme's ability to bind its substrate and catalyze the reaction.

Question 19

Which of the following is TRUE regarding the turnover number of an enzyme?

Accepted Answer

It refers to the number of substrate molecules converted to product per enzyme per second.

Question 20

Which of the following is a correct pairing of enzyme class and reaction type?

Accepted Answer

Isomerase: rearrangement of atoms within a molecule

Microbial Metabolism: Catabolic and Anabolic Reactions, Enzymes, and Energy

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