Question 1

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

Accepted Answer

A pathway that can function in both catabolic and anabolic processes, such as the citric acid cycle.

Question 2

Sulfanilamide acts as an inhibitor by mimicking the substrate for an enzyme involved in folic acid synthesis. What type of inhibition does this represent?

Accepted Answer

Competitive inhibition

Question 3

During glycolysis, glucose is converted to pyruvate. Which of the following correctly represents the net ATP and NADH produced per molecule of glucose?

Accepted Answer

Net gain of $$2$$ ATP and $$2$$ NADH

Question 4

Which enzyme protects bacteria from the toxic effects of superoxide radicals ($$O_2$$^-$$)?

Accepted Answer

Superoxide dismutase

Question 5

A bacterial culture starts with $$100$$ cells. If the population doubles every $$30$$ minutes, how many cells will there be after $$2$$ hours?

Accepted Answer

After $$2$$ hours ($$120$$ minutes), there are $$4$$ generations: $$n = 4. $$Total cells $$= 100 	imes 2^4$ = 100 	imes 16 = 1600.$$

Question 6

Which of the following best explains why cells perform fermentation?

Accepted Answer

To replenish NAD$$^+$$ for glycolysis when oxygen is unavailable.

Question 7

Which of the following statements about DNA replication is correct?

Accepted Answer

DNA replication is semiconservative, each new molecule contains one old and one new strand.

Question 8

Which of the following is NOT a mechanism by which bacteria can resist antibiotics?

Accepted Answer

Increasing permeability to the antibiotic

Question 9

Which of the following best describes the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation uses a direct transfer of phosphate from a substrate to ADP, while oxidative phosphorylation uses energy from electron transport and chemiosmosis.

Question 10

Which of the following is a characteristic of an obligate anaerobe?

Accepted Answer

Cannot tolerate oxygen and lacks enzymes to detoxify reactive oxygen species.

Question 11

Which of the following best describes the role of the bacterial pilus in conjugation?

Accepted Answer

It transfers DNA from one bacterium to another by direct contact.

Question 12

Which of the following is the correct sequence for the catabolism of glucose in aerobic respiration?

Accepted Answer

Glycolysis $$\rightarrow$$ Acetyl-CoA synthesis $$\rightarrow$$ Citric acid cycle $$\rightarrow$$ Electron transport chain

Question 13

Which of the following is a plausible outcome of exposure to a mutagen?

Accepted Answer

A silent, missense, nonsense, or frameshift mutation.

Question 14

Which of the following best describes the function of ATP in cellular metabolism?

Accepted Answer

ATP serves as the primary energy currency, transferring energy for cellular processes.

Question 15

Which of the following is true regarding the Kirby-Bauer Susceptibility Test?

Accepted Answer

It uses agar plates to assess the effectiveness of antibiotics by measuring zones of inhibition.

Question 16

Which of the following is a reason why antifungal agents are fewer than antibacterial agents?

Accepted Answer

Fungi are eukaryotes, making it harder to find drugs that are selectively toxic.

Question 17

Which of the following best describes the mechanism of action of beta-lactam antibiotics?

Accepted Answer

They inhibit cell wall synthesis by blocking peptidoglycan cross-linking.

Question 18

Which of the following is a correct description of the Ames test?

Accepted Answer

It detects mutagenic potential of chemicals by measuring the rate of mutation in bacteria.

Question 19

Which of the following best describes feedback inhibition in metabolic pathways?

Accepted Answer

The end product of a pathway inhibits an enzyme early in the pathway, preventing overproduction.

Microbial Metabolism, Growth, Genetics, Control, and Antimicrobial Agents: Study Guide for BIOL 2420 Exam #2

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