Question 1

Which of the following best explains why penicillin exhibits selective toxicity?

Accepted Answer

Penicillin inhibits peptidoglycan synthesis, a component unique to bacterial cell walls.

Question 2

A patient is diagnosed with a Gram-negative bacterial infection. Which antibiotic would be LEAST effective due to its inability to cross the outer membrane?

Accepted Answer

Daptomycin

Question 3

Which of the following drugs inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit and blocking tRNA binding?

Accepted Answer

Tetracyclines

Question 4

A patient with tuberculosis is prescribed isoniazid. What is the primary target of this drug?

Accepted Answer

Mycolic acid synthesis

Question 5

Which combination of drugs is bactericidal due to their synergistic inhibition of folic acid synthesis?

Accepted Answer

Sulfonamides and trimethoprim

Question 6

A new antibiotic is found to inhibit DNA gyrase. Which class does it most likely belong to?

Accepted Answer

Fluoroquinolones

Question 7

Which of the following best describes the mechanism of action of vancomycin?

Accepted Answer

Binds to peptidoglycan subunits, preventing their incorporation into the cell wall.

Question 8

A patient with a fungal infection is treated with a drug that targets ergosterol. What is the likely effect of this drug?

Accepted Answer

Disruption of the fungal cell membrane integrity

Question 9

Which of the following statements about polymyxins is correct?

Accepted Answer

They disrupt the outer membrane of Gram-negative bacteria, causing cell leakage.

Question 10

Acyclovir is used to treat herpes infections. What is the basis for its selective toxicity?

Accepted Answer

It is activated only by a viral enzyme present in herpes-infected cells.

Question 11

Which of the following best explains why sulfonamides are bacteriostatic when used alone?

Accepted Answer

They block the conversion of PABA to dihydrofolic acid, halting folic acid synthesis.

Question 12

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

Accepted Answer

Daptomycin – Gram-positive cell membrane

Question 13

A patient is prescribed an antibiotic that is excreted quickly and must be taken multiple times per day. Which pharmacokinetic property does this illustrate?

Accepted Answer

Rapid metabolism and excretion

Question 14

Which of the following best describes the action of macrolides?

Accepted Answer

Bind to the 50S ribosomal subunit and inhibit peptide bond formation

Question 15

A patient with a severe bacterial infection is given a broad-spectrum antibiotic. What is a potential risk of this treatment?

Accepted Answer

Disruption of normal microbiota, leading to secondary infections

Question 16

Which of the following drugs is only active in anaerobic cells and binds to DNA to exert its effect?

Accepted Answer

Metronidazole

Question 17

A patient is being treated for HIV. Which drug class blocks the integration of viral DNA into the host genome?

Accepted Answer

Integrase inhibitors

Question 18

Which of the following best describes the mechanism of action of cephalosporins?

Accepted Answer

Bind to penicillin-binding proteins, inhibiting peptidoglycan cross-linking

Question 19

A patient is prescribed a topical antibiotic for a skin infection. Which route of administration is being used?

Accepted Answer

Topical

Question 20

Which of the following is a correct statement about the spectrum of activity of antibiotics?

Accepted Answer

Broad-spectrum antibiotics can target a wide range of bacteria, including both Gram-positive and Gram-negative species.

Antimicrobial Drugs: Mechanisms, Targets, and Clinical Applications

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