Question 1

Which of the following best describes the difference between catabolism and anabolism in microbial metabolism?

Accepted Answer

Catabolism involves the breakdown of molecules to release energy, while anabolism uses energy to build complex molecules.

Question 2

A patient’s wound culture grows a bacterium that tests positive in the oxidase test. What does this result indicate about the bacterium’s metabolism?

Accepted Answer

It possesses cytochrome c oxidase and likely uses oxygen as a terminal electron acceptor in aerobic respiration.

Question 3

Which of the following equations correctly represents the net ATP yield from aerobic respiration of one molecule of glucose in prokaryotes?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + 38ATP$$

Question 4

Which of the following best describes a chemoautotroph?

Accepted Answer

An organism that uses inorganic chemicals as an energy source and CO$$_2 as a $$carbon source.

Question 5

A bacterial culture is exposed to a chemical that denatures proteins. Which enzyme property is most directly affected?

Accepted Answer

The three-dimensional structure of the enzyme’s active site.

Question 6

Which of the following is a key difference between fermentation and aerobic respiration in bacteria?

Accepted Answer

Fermentation uses an organic molecule as the final electron acceptor, while aerobic respiration uses oxygen.

Question 7

During the stationary phase of a bacterial growth curve, which of the following best explains why the number of viable cells remains constant?

Accepted Answer

The rate of cell division equals the rate of cell death due to nutrient depletion and waste accumulation.

Question 8

Which enzyme is essential for obligate aerobes to survive in the presence of oxygen by detoxifying superoxide radicals?

Accepted Answer

Superoxide dismutase

Question 9

A microbe that grows optimally at 55°C and can survive at temperatures up to 70°C is best classified as which of the following?

Accepted Answer

Thermophile

Question 10

Which of the following best describes an obligate halophile?

Accepted Answer

A microbe that requires high salt concentrations for growth due to osmotic adaptation.

Question 11

Which of the following terms refers to the complete removal or destruction of all forms of microbial life, including endospores?

Accepted Answer

Sterilization

Question 12

Which of the following is an example of a -cidal treatment?

Accepted Answer

A chemical that kills bacteria on a surgical instrument.

Question 13

Which of the following is a physical method of microbial control that works by denaturing proteins and disrupting membranes?

Accepted Answer

Moist heat (autoclaving)

Question 14

A patient is prescribed a broad-spectrum antibiotic. What is a significant risk associated with this treatment?

Accepted Answer

Development of a superinfection due to disruption of normal microbiota.

Question 15

Which of the following mechanisms of action is most likely for an antibacterial drug that inhibits peptidoglycan synthesis?

Accepted Answer

Inhibition of cell wall biosynthesis

Question 16

A patient is given two drugs that, when combined, have a greater effect than either alone. What is this interaction called?

Accepted Answer

Synergism

Question 17

Which of the following best explains how bacteria can acquire resistance genes from other bacteria through direct cell-to-cell contact?

Accepted Answer

Conjugation

Question 18

A patient with a fungal infection is treated with a drug that targets ergosterol synthesis. Why is this drug less likely to harm human cells?

Accepted Answer

Human cell membranes contain cholesterol instead of ergosterol.

Question 19

Which of the following is a common mechanism by which bacteria develop resistance to beta-lactam antibiotics?

Accepted Answer

Production of beta-lactamase enzymes that hydrolyze the antibiotic.

Question 20

A facultative anaerobe is placed in an environment with no oxygen. Which metabolic pathway will it most likely use to generate ATP?

Accepted Answer

Fermentation

Microbial Metabolism, Growth, Control, and Antimicrobial Drugs – Study Guide

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