Question 1

Which of the following is a major reason why it is difficult to develop antiviral drugs with selective toxicity?

Accepted Answer

Viruses use host cell machinery for replication, making it hard to target the virus without harming host cells.

Question 2

Beta-lactam antibiotics, such as penicillin, inhibit bacterial growth by interfering with which cellular process?

Accepted Answer

Transpeptidation during cell wall synthesis

Question 3

A patient is infected with a Gram-negative bacterium that produces beta-lactamase. Which antibiotic would likely be most effective?

Accepted Answer

Cephalosporin

Question 4

Which mechanism of resistance allows bacteria to survive sulfa drug treatment?

Accepted Answer

Uptake of folic acid from the environment instead of synthesizing it

Question 5

Why do broad-spectrum antibiotics increase the risk of superinfection?

Accepted Answer

They kill nonresistant normal microbiota, allowing drug-resistant pathogens to proliferate.

Question 6

Which of the following is a correct description of the action of quinolones?

Accepted Answer

Quinolones disrupt DNA gyrase, preventing DNA replication and transcription.

Question 7

Which equation best represents the relationship between plasma concentration of an antibiotic and time after administration?

Accepted Answer

$$C(t) = C_0$ e$$^{-kt}$$

Question 8

Which of the following is NOT a common target for antimicrobial drugs?

Accepted Answer

Mitochondrial DNA replication in bacteria

Question 9

A combination therapy of sulfa drugs and trimethoprim is effective because:

Accepted Answer

It blocks two sequential steps in folic acid synthesis, reducing the chance of resistance.

Question 10

Which of the following statements about antimicrobial resistance is TRUE?

Accepted Answer

Antimicrobial resistance is pre-existing and is selected for by antibiotic use.

Question 11

Which of the following is a major challenge in developing antifungal drugs?

Accepted Answer

Fungi are eukaryotic and share many cellular features with human cells.

Question 12

Which of the following is a potential virulence factor of Staphylococcus aureus that contributes to its ability to cause disease?

Accepted Answer

Production of toxins and enzymes that damage host tissues

Question 13

Why are only about 1% of antibiotics isolated from nature clinically useful?

Accepted Answer

Most are toxic to humans or lack sufficient activity against pathogens.

Question 14

Which of the following best explains why combination therapy is used in HIV treatment?

Accepted Answer

It targets multiple steps in the viral life cycle, reducing the likelihood of resistance.

Question 15

Which of the following mechanisms allows bacteria to inactivate beta-lactam antibiotics?

Accepted Answer

Production of beta-lactamase enzymes

Question 16

Which of the following is a correct application of the concept of selective toxicity in antimicrobial drug design?

Accepted Answer

Targeting bacterial cell wall synthesis, which is absent in human cells

Question 17

A new antibiotic is found to inhibit the 50S ribosomal subunit. Which type of microorganism is it most likely to affect?

Accepted Answer

Bacteria

Question 18

Which of the following is a plausible reason for the decline in new antimicrobial drug approvals by the FDA from 1983 to 2012?

Accepted Answer

Increasing difficulty in finding drugs that are both effective and safe for humans

Question 19

Which of the following best describes the mechanism of action of Tamiflu (oseltamivir)?

Accepted Answer

It inhibits neuraminidase, preventing the release of new influenza virus particles from infected cells.

Question 20

Which of the following strategies is LEAST likely to be effective in isolating new antibiotics?

Accepted Answer

Only testing antibiotics that are already used clinically

Antibiotics and Antibiotic Resistance: Mechanisms, Challenges, and New Developments

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