Question 1

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

Accepted Answer

Catabolic pathways break down macromolecules and release energy, while anabolic pathways synthesize macromolecules and require energy.

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 fermentation is essential for some cells under anaerobic conditions?

Accepted Answer

Fermentation regenerates NAD$$^+$$, allowing glycolysis to continue in the absence of an electron transport chain.

Question 4

Which of the following is the correct sequence of events in aerobic cellular respiration?

Accepted Answer

Glycolysis → Synthesis of Acetyl-CoA → Krebs cycle → Electron Transport Chain

Question 5

Which of the following electron carriers is reduced during the Krebs cycle?

Accepted Answer

NAD$$^+$$ and FAD

Question 6

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

Accepted Answer

To create a proton gradient that drives ATP synthesis via chemiosmosis

Question 7

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Competitive inhibitors block the active site, preventing substrate binding.

Question 8

In the transition step (synthesis of acetyl-CoA), which of the following occurs?

Accepted Answer

Pyruvate is converted to acetyl-CoA, CO$$_2 is $$released, and NAD$$^+ is $$reduced to NADH.

Question 9

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

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

Question 10

Which of the following is a product of homolactic fermentation?

Accepted Answer

Lactic acid

Question 11

Which of the following best explains why enzymes are considered biological catalysts?

Accepted Answer

They lower the activation energy and are not permanently changed by the reaction.

Question 12

Which of the following is NOT a possible final electron acceptor in anaerobic respiration?

Accepted Answer

O$$_2$$

Question 13

Which pathway yields the highest number of ATP molecules per molecule of glucose?

Accepted Answer

Aerobic respiration

Question 14

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

Accepted Answer

To slow or stop anabolic pathways when the end product is abundant

Question 15

Which of the following statements about the pentose phosphate pathway is correct?

Accepted Answer

It generates NADPH and precursor metabolites for anabolic reactions.

Question 16

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

Accepted Answer

It acts as an electron carrier, accepting electrons during catabolic reactions.

Question 17

Which of the following is an example of an amphibolic pathway?

Accepted Answer

Krebs cycle

Question 18

Which of the following is true regarding the location of the Krebs cycle in prokaryotes and eukaryotes?

Accepted Answer

It occurs in the cytoplasm of prokaryotes and the mitochondrial matrix of eukaryotes.

Question 19

Which of the following best describes the process of chemiosmosis?

Accepted Answer

The movement of protons down their electrochemical gradient through ATP synthase to generate ATP.

Question 20

Which of the following is a direct product of the decarboxylation of pyruvate during the transition step?

Accepted Answer

Acetyl-CoA

Microbial Metabolism: Catabolic and Anabolic Pathways

Study Guide - Practice Questions