Question 1

Which of the following statements best describes the role of enzymes in microbial metabolism?

Accepted Answer

Enzymes lower the activation energy required for reactions, allowing metabolic processes to occur at rates compatible with life.

Question 2

A holoenzyme is composed of which of the following components?

Accepted Answer

Apoenzyme and cofactor

Question 3

Which metabolic pathway is responsible for the complete oxidation of glucose to carbon dioxide and water, and what is the net ATP yield in prokaryotes?

Accepted Answer

Aerobic respiration; $38$ ATP

Question 4

During glycolysis, glucose is enzymatically converted to which intermediate, and is oxygen required for this process?

Accepted Answer

Pyruvic acid; oxygen is not required

Question 5

Which of the following is NOT a characteristic of enzymes?

Accepted Answer

Enzymes are permanently changed by the reactions they catalyze.

Question 6

A patient is infected with a bacterium that produces penicillinase. What is the clinical significance of this enzyme?

Accepted Answer

It hydrolyzes the beta-lactam ring of penicillin, rendering the antibiotic ineffective.

Question 7

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation uses organic compounds as terminal electron acceptors and produces a small amount of ATP.

Question 8

In the electron transport system (ETS) of aerobic respiration, what is the final electron acceptor?

Accepted Answer

Molecular oxygen ($O_2$)

Question 9

Which of the following metabolic intermediates can be diverted from glycolysis to serve as a precursor for amino acid, carbohydrate, and triglyceride synthesis?

Accepted Answer

Glyceraldehyde-3-phosphate ($G3P$)

Question 10

Which process describes the generation of ATP by transferring a phosphate group directly from a phosphorylated compound to ADP?

Accepted Answer

Substrate-level phosphorylation

Question 11

A bacterium is found to reduce nitrate ($NO_3^-$) to nitrite ($NO_2^-$) and water. Which metabolic pathway is this organism using?

Accepted Answer

Anaerobic respiration

Question 12

Which of the following is true regarding the Krebs cycle?

Accepted Answer

Each glucose molecule results in two spins of the Krebs cycle, producing reduced NADH and FADH$_2$.

Question 13

Which of the following statements about catabolism of fatty acids is correct?

Accepted Answer

Beta-oxidation of a 6-carbon fatty acid yields more ATP than the complete oxidation of a 6-carbon sugar.

Question 14

Which of the following is NOT a precursor molecule for biosynthesis in microbial cells?

Accepted Answer

Lactic acid

Question 15

Which statement best explains why enzymes are considered virulence factors in pathogenic microbes?

Accepted Answer

They contribute to pathogenicity by breaking down host tissues or evading immune responses.

Question 16

Which of the following is true about the light-dependent reactions of photosynthesis?

Accepted Answer

They proceed only in the presence of sunlight and produce ATP and NADPH.

Question 17

Which pigment is utilized by green and purple bacteria for anoxygenic photosynthesis?

Accepted Answer

Bacteriochlorophyll

Question 18

A mutation causes an enzyme to lose its tertiary structure due to high temperature. What is the most likely consequence?

Accepted Answer

The enzyme becomes denatured and loses its function, blocking metabolic reactions.

Question 19

Which of the following statements about amino acid metabolism is correct?

Accepted Answer

Amino acids can be deaminated and converted into intermediates of the Krebs cycle.

Question 20

Which of the following is a correct equation for photosynthesis in microbes?

Accepted Answer

$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

Microbial Metabolism: An Overview

Study Guide - Practice Questions

Study Guide - Flashcards