Question 1

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

Accepted Answer

Catabolic pathways release energy by breaking down complex 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 statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy, increasing the likelihood of a reaction.

Question 4

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

Accepted Answer

Fermentation

Question 5

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

Accepted Answer

$$6$$ $$CO_2$

Question 6

What is the main function of the electron transport chain in cellular respiration?

Accepted Answer

To use energy from electrons to pump protons and generate ATP via chemiosmosis

Question 7

Which of the following best explains why oxygen is required for aerobic respiration?

Accepted Answer

Oxygen is the final electron acceptor in the electron transport chain.

Question 8

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is generated by the direct transfer of a phosphate group to ADP from a phosphorylated intermediate.

Question 9

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

Accepted Answer

Glycolysis

Question 10

Which of the following is a function of feedback inhibition in metabolic pathways?

Accepted Answer

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

Question 11

Which of the following best describes the role of NADH and FADH$$_2 in $$cellular respiration?

Accepted Answer

They carry electrons from catabolic reactions to the electron transport chain.

Question 12

Which of the following is true regarding the pentose phosphate pathway?

Accepted Answer

It produces NADPH and pentoses and operates alongside glycolysis.

Question 13

A patient is given a drug that acts as a competitive inhibitor for a bacterial enzyme. Which of the following best describes how this drug works?

Accepted Answer

It binds to the active site, preventing substrate binding.

Question 14

Which of the following is a correct statement about the energy yield from aerobic respiration of one molecule of glucose in prokaryotes?

Accepted Answer

$$38$$ ATP$

Question 15

Which of the following is NOT a function of enzymes in metabolism?

Accepted Answer

Being consumed and permanently altered during reactions

Question 16

Which of the following best explains why fermentation is less efficient than aerobic respiration?

Accepted Answer

Fermentation does not use the electron transport chain, so less ATP is produced per glucose molecule.

Question 17

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

Accepted Answer

Isomerases – rearrange atoms within a molecule

Question 18

A bacterial cell is exposed to a noncompetitive inhibitor. What is the most likely effect on the enzyme's activity?

Accepted Answer

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

Question 19

Which of the following is a correct description of oxidative phosphorylation?

Accepted Answer

ATP is produced using energy from a proton gradient created by the electron transport chain.

Question 20

Which of the following is a real-world example of feedback inhibition in microbial metabolism?

Accepted Answer

A bacterium stops producing an amino acid when the amino acid is abundant, by inhibiting the first enzyme in its biosynthetic pathway.

Microbial Metabolism: Catabolism, Anabolism, and Energy Production

Study Guide - Practice Questions