Question 1

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

Accepted Answer

The drug must be more toxic to the pathogen than the host.

Question 2

Why are there many antibacterial drugs but fewer antifungal and antiviral drugs?

Accepted Answer

Bacteria have more differences from human cells, providing more drug targets.

Question 3

Which of the following drugs inhibits bacterial cell wall synthesis by binding enzymes that form cross bridges between NAMs?

Accepted Answer

Penicillins

Question 4

A patient is prescribed an azole for a yeast infection. What is the mechanism of action of this drug?

Accepted Answer

Inhibits ergosterol synthesis in fungal cell membranes

Question 5

Which of the following statements about sulfonamides is correct?

Accepted Answer

They block nucleotide synthesis by preventing folic acid synthesis.

Question 6

Which of the following drugs is used to inhibit nucleic acid synthesis in viruses by acting as a base analog?

Accepted Answer

Acyclovir

Question 7

A broad-spectrum antimicrobial drug is most likely to cause which of the following complications?

Accepted Answer

Opportunistic (secondary) infections due to loss of microbial antagonism

Question 8

Which ribosomal subunits are targeted by drugs that inhibit protein synthesis in prokaryotes?

Accepted Answer

$$70S ($$composed of $$30S$$ and $$50S$$ subunits)

Question 9

Which of the following is a disadvantage of narrow-spectrum antimicrobial drugs?

Accepted Answer

They have fewer applications due to limited range of activity.

Question 10

A patient with a herpes simplex virus infection is treated with a fusion inhibitor. What is the primary mechanism of action?

Accepted Answer

Prevents viral entry by blocking fusion with the host cell membrane

Question 11

Which of the following is NOT a mechanism of action for antimicrobial drugs?

Accepted Answer

Stimulation of host immune response

Question 12

Which drug would be most appropriate for treating a respiratory syncytial virus (RSV) infection?

Accepted Answer

Ribavirin

Question 13

Which of the following best explains why azoles are selectively toxic to fungi but not humans?

Accepted Answer

Fungi synthesize ergosterol, while humans synthesize cholesterol.

Question 14

Which of the following is a chemotherapeutic drug but NOT an antimicrobial drug?

Accepted Answer

Insulin

Question 15

A patient develops a secondary infection after taking a broad-spectrum antibiotic. What is the most likely cause?

Accepted Answer

Loss of microbial antagonism due to disruption of resident microbiota

Question 16

Which of the following drugs acts by inhibiting the attachment of HIV to host cells?

Accepted Answer

T20

Question 17

Which of the following is a correct match between drug and its mechanism of action?

Accepted Answer

Streptomycin – inhibits protein synthesis by binding to the $$30S$$ ribosomal subunit

Question 18

Which of the following would be LEAST likely to be targeted by an antimicrobial drug due to similarity with host cell structures?

Accepted Answer

Human ribosomes

Question 19

A new drug is developed that blocks the synthesis of peptidoglycan. Which type of microorganism would this drug be most effective against?

Accepted Answer

Bacteria

Question 20

Which of the following is a major advantage of broad-spectrum antimicrobial drugs?

Accepted Answer

They can be used to treat infections caused by multiple types of pathogens.

Controlling Microbial Growth in the Body: Antimicrobial Drugs (Lecture 9, Part I)

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