Question 1

Which of the following best describes the principle of selective toxicity in antimicrobial drugs?

Accepted Answer

The drug targets microbial structures or functions not found in the host, minimizing harm to the host.

Question 2

A patient is prescribed an antibiotic for a bacterial infection. After a few days, the patient feels better and stops taking the medication early. What is the most likely consequence of this action?

Accepted Answer

The remaining bacteria may be more resistant, increasing the risk of a recurrent, harder-to-treat infection.

Question 3

Which of the following is NOT a characteristic of an ideal antimicrobial drug?

Accepted Answer

It is expensive and requires refrigeration.

Question 4

Why are most antimicrobial drugs more effective against bacteria than viruses?

Accepted Answer

Bacteria have unique structures such as cell walls and ribosomes that can be targeted, while viruses use host cell machinery, leaving fewer unique targets.

Question 5

Which of the following antibiotics targets bacterial cell wall synthesis?

Accepted Answer

Penicillin

Question 6

A hospital survey found that over 60% of antibiotics were prescribed in the wrong dosage or for ineffective applications. What is a likely consequence of this practice?

Accepted Answer

It will encourage the development and spread of antibiotic-resistant microbes.

Question 7

Which of the following best explains why combination therapy (using multiple antibiotics) is used to treat diseases like tuberculosis?

Accepted Answer

It reduces the likelihood that any single bacterium will be resistant to all drugs simultaneously.

Question 8

Which of the following statements about drug resistance is TRUE?

Accepted Answer

Drug resistance is a result of natural selection acting on microbial populations.

Question 9

Which of the following is a broad-spectrum antibiotic most likely to do?

Accepted Answer

Disrupt normal flora, increasing the risk of superinfection.

Question 10

Which of the following best describes the mechanism of action of sulfa drugs?

Accepted Answer

They inhibit bacterial enzymes involved in folic acid synthesis.

Question 11

A patient develops a yeast infection after taking antibiotics for a bacterial infection. This is an example of:

Accepted Answer

Superinfection

Question 12

Which of the following statements about the evolution of antibiotic resistance is correct?

Accepted Answer

Antibiotic resistance can be spread by microbial conjugation.

Question 13

Which of the following drugs targets bacterial ribosomes?

Accepted Answer

Streptomycin

Question 14

Why are antimicrobial drugs generally less effective against fungi, protozoans, and helminths compared to bacteria?

Accepted Answer

They are eukaryotic and share more similarities with human cells, reducing selective drug targets.

Question 15

Which of the following is a reason why antibiotics should not be prescribed for viral infections such as bronchitis?

Accepted Answer

Antibiotics can disrupt normal flora and promote resistance without affecting the virus.

Question 16

Which of the following is a correct pairing of an antibiotic and its primary target?

Accepted Answer

Polymyxin B – plasma membrane

Question 17

If a bacterial population is exposed to an antibiotic, which of the following best describes what happens over time according to the principles of natural selection?

Accepted Answer

Resistant bacteria survive and reproduce, increasing the frequency of resistance genes.

Question 18

Which of the following is a key reason why it is important for an antimicrobial drug to be soluble?

Accepted Answer

So it can penetrate body tissues and reach the site of infection.

Question 19

Which of the following best explains why resistance genes may be disadvantageous to bacteria in the absence of antibiotics?

Accepted Answer

They divert metabolic energy towards unneeded products, reducing fitness.

Question 20

A new antibiotic is discovered that targets a structure unique to prokaryotes. Which of the following is the most likely target?

Accepted Answer

Peptidoglycan cell wall

Study Notes: Antimicrobial Drugs and Drug Resistance (Chapter 20)

Study Guide - Practice Questions

Study Guide - Flashcards