Question 1

Which of the following best describes an amphibolic pathway in microbial metabolism?

Accepted Answer

A pathway that can function in both breaking down and building molecules.

Question 2

During cellular respiration, which molecule acts as the final electron acceptor in aerobic organisms?

Accepted Answer

Oxygen ($O_2$)

Question 3

Which process directly transfers a phosphoryl group from a high-energy substrate to ADP to form ATP?

Accepted Answer

Substrate-level phosphorylation

Question 4

A patient’s cells are unable to use oxygen as the final electron acceptor. Which metabolic pathway will be least efficient for ATP production?

Accepted Answer

Fermentation

Question 5

Which coenzyme acts as an electron carrier and is reduced during glycolysis?

Accepted Answer

NADH

Question 6

What is the net gain of ATP molecules for each glucose molecule oxidized during glycolysis?

Accepted Answer

$2$

Question 7

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes are biological catalysts that lower activation energy.

Question 8

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate access.

Question 9

Which of the following is a correct description of oxidation and reduction in redox reactions?

Accepted Answer

Oxidation is the loss of electrons; reduction is the gain of electrons.

Question 10

In the electron transport chain of prokaryotes, where are the electron carrier molecules located?

Accepted Answer

Plasma membrane

Question 11

Which metabolic pathway is responsible for the complete oxidation of acetyl-CoA to $CO_2$?

Accepted Answer

Krebs cycle (Citric Acid Cycle)

Question 12

If a cell is deprived of NAD+, which process will be directly affected first?

Accepted Answer

Glycolysis

Question 13

Which of the following is NOT a product of the Krebs cycle?

Accepted Answer

Pyruvate

Question 14

Which process is responsible for generating the proton motive force used by ATP synthase?

Accepted Answer

Electron transport chain

Question 15

A cell is observed to produce methane ($CH_4$) as a final product. Which final electron acceptor is most likely used?

Accepted Answer

Carbonate ($CO_3^{2-}$)

Question 16

Which statement best explains why fats yield more ATP than carbohydrates during cellular respiration?

Accepted Answer

Fats contain more hydrocarbon bonds, which are highly reduced and store more electrons.

Question 17

Which of the following is TRUE about fermentation?

Accepted Answer

Fermentation sustains ATP production when respiratory chains are unavailable.

Question 18

Which process allows bacteria to synthesize glucose from non-sugar precursors?

Accepted Answer

Gluconeogenesis

Question 19

Apoenzyme refers to:

Accepted Answer

An enzyme without its cofactor (inactive form)

Question 20

Which of the following is an example of an organic cofactor required by enzymes?

Accepted Answer

NAD+

Microbial Metabolism: Principles and Pathways

Study Guide - Practice Questions