Question 1

Which of the following best describes a catabolic pathway in microbial metabolism?

Accepted Answer

A pathway that breaks down macromolecules into simpler components, releasing energy.

Question 2

Which process is illustrated by the equation below?

$$	ext{A} + 	ext{B} ightarrow 	ext{AB} + 	ext{H}_2	ext{O}$$

This reaction requires energy input and releases water.

Accepted Answer

Dehydration synthesis (anabolism)

Question 3

Which of the following statements about enzymes is FALSE?

Accepted Answer

Enzymes are permanently altered after catalyzing a reaction.

Question 4

A competitive inhibitor of an enzyme acts by:

Accepted Answer

Binding to the active site, preventing substrate binding.

Question 5

Which of the following is an example of a coenzyme involved in catabolic reactions?

Accepted Answer

NAD+

Question 6

What is the main advantage of using enzymes to catalyze reactions in living cells?

Accepted Answer

They allow reactions to occur at lower temperatures, preventing protein denaturation.

Question 7

Which of the following factors does NOT directly affect enzyme activity?

Accepted Answer

Oxygen concentration

Question 8

In the context of redox reactions, which statement is correct?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 9

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated directly by transferring a phosphate group from a substrate to ADP.

Question 10

During aerobic respiration in prokaryotes, what is the maximum theoretical yield of ATP per molecule of glucose?

Accepted Answer

$$38$$

Question 11

Which of the following is NOT a characteristic of fermentation?

Accepted Answer

It produces large amounts of ATP.

Question 12

Which of the following best explains why feedback inhibition is important in metabolic pathways?

Accepted Answer

It prevents the overaccumulation of end-products by inhibiting an early enzyme in the pathway.

Question 13

Which of the following vitamins is a precursor for NAD+ and NADP+ coenzymes?

Accepted Answer

Niacin (Nicotinic Acid)

Question 14

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

Accepted Answer

It binds to an allosteric site, changing the enzyme's shape and reducing its activity.

Question 15

Which of the following is a correct summary of the energy yield from glycolysis per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, 2 pyruvate

Question 16

Which of the following best describes the role of oxygen in aerobic respiration?

Accepted Answer

It acts as the final electron acceptor in the electron transport chain.

Question 17

Which of the following statements about the electron transport chain (ETC) is TRUE?

Accepted Answer

The ETC uses a series of redox reactions to transfer electrons and generate a proton gradient.

Question 18

Which of the following is a reason why some cells rely on fermentation instead of respiration?

Accepted Answer

They lack genes for the Krebs cycle or electron transport chain.

Question 19

Which of the following best describes the fate of fatty acids during lipid catabolism in microbes?

Accepted Answer

They are broken down by lipases and enter the Krebs cycle as acetyl-CoA.

Question 20

Amino acids are deaminated before entering the Krebs cycle. What is the primary reason for this step?

Accepted Answer

To remove the amino group, allowing the carbon skeleton to enter the Krebs cycle.

Microbial Metabolism: Structure, Function, and Regulation

Study Guide - Practice Questions