Question 1

Which of the following statements best describes the relationship between catabolic and anabolic pathways in microbial metabolism?

Accepted Answer

Catabolic pathways release energy by breaking down molecules, and anabolic pathways use that energy to synthesize macromolecules.

Question 2

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 3

Which of the following best explains why enzymes are essential for metabolic reactions?

Accepted Answer

They lower the activation energy, increasing the likelihood of reactions occurring.

Question 4

A bacterium is growing in an environment lacking oxygen. Which metabolic pathway will it most likely use to regenerate NAD+ for glycolysis?

Accepted Answer

Fermentation

Question 5

Which of the following is NOT a product of the Krebs cycle per molecule of glucose?

Accepted Answer

$$4$$ NADP^+$

Question 6

In the electron transport chain, what is the primary function of the proton gradient across the membrane?

Accepted Answer

To drive the synthesis of ATP via ATP synthase

Question 7

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated by the transfer of a phosphate group from a substrate to ADP.

Question 8

A mutation in a bacterium prevents the production of NAD+. Which process would be most directly affected?

Accepted Answer

Glycolysis

Question 9

Which of the following is a correct pairing of an electron carrier and its reduced form?

Accepted Answer

NADP+ and NADPH

Question 10

Which of the following statements about feedback inhibition is correct?

Accepted Answer

The end product of a metabolic pathway inhibits an enzyme that acts early in the pathway.

Question 11

Which of the following is a characteristic of competitive enzyme inhibition?

Accepted Answer

The inhibitor binds to the active site, blocking substrate binding.

Question 12

Which of the following best explains why the electron transport chain produces more ATP than glycolysis?

Accepted Answer

It uses oxygen as the final electron acceptor, allowing for complete oxidation of glucose.

Question 13

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

Accepted Answer

The enzyme's active site is distorted, reducing its activity regardless of substrate concentration.

Question 14

Which of the following is a direct result of the decarboxylation reactions in the Krebs cycle?

Accepted Answer

Release of $$CO_2$$

Question 15

Which pathway is unique to some bacteria and produces both NADPH and ATP without involving glycolysis?

Accepted Answer

Entner-Doudoroff pathway

Question 16

In oxidative phosphorylation, what is the role of ATP synthase?

Accepted Answer

It uses the proton gradient to convert ADP and inorganic phosphate into ATP.

Question 17

Which of the following is a correct description of the induced fit model of enzyme activity?

Accepted Answer

The enzyme changes shape slightly to fit the substrate upon binding.

Question 18

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

Accepted Answer

The enzymes may denature, losing their functional shape.

Question 19

Which of the following is a function of the pentose phosphate pathway?

Accepted Answer

It generates NADPH and ribose-5-phosphate for biosynthetic reactions.

Question 20

During aerobic respiration, what is the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Microbial Metabolism: An Overview of Catabolic and Anabolic Pathways

Study Guide - Practice Questions