$$\text{Sulfonamide} + \text{Enzyme} \rightarrow \text{No Dihydrofolic acid}$$

$$\text{Fluoroquinolone} + \text{DNA gyrase} \rightarrow \text{No DNA replication}$$

$$\text{Penicillin} + \text{Transpeptidase} \rightarrow \text{No peptide cross-link}$$

Question 1

Which characteristic is most important for an antimicrobial drug to minimize harm to the patient?

Accepted Answer

It should be selectively toxic to the microbe but nontoxic to host cells.

Question 2

A patient is prescribed penicillin for a bacterial infection. Which mechanism best describes how penicillin acts on bacteria?

Accepted Answer

Penicillin blocks transpeptidase enzyme, preventing peptide cross-links between NAM subunits in peptidoglycan.

Question 3

Why are beta-lactam antibiotics generally ineffective against non-growing bacteria?

Accepted Answer

Non-growing bacteria do not synthesize new cell walls, so beta-lactams cannot disrupt peptidoglycan formation.

Question 4

Which equation best represents the competitive inhibition of folic acid synthesis by sulfonamides?

Accepted Answer

$$	ext{Sulfonamide} + 	ext{Enzyme} ightarrow 	ext{No Dihydrofolic acid}$$

Question 5

A patient develops a rash and hives after taking amoxicillin. What is the most likely cause?

Accepted Answer

Abnormal immune reaction to the drug.

Question 6

Which Nobel laureate is credited with discovering the first antibiotic, penicillin?

Accepted Answer

Alexander Fleming

Question 7

What is the primary reason why vancomycin is effective against MRSA (Methicillin Resistant Staphylococcus aureus)?

Accepted Answer

It binds to the D-Ala-D-Ala portion of peptidoglycan monomers, blocking transpeptidase activity.

Question 8

Which antibiotic is most likely to cause bone marrow toxicity and is reserved as a last-resort drug?

Accepted Answer

Chloramphenicol

Question 9

A child is prescribed tetracycline for a bacterial infection. What side effect should the physician warn about?

Accepted Answer

Discoloration of teeth and bones due to calcium complex formation

Question 10

Which equation best represents the inhibition of bacterial DNA synthesis by fluoroquinolones?

Accepted Answer

$$	ext{Fluoroquinolone} + 	ext{DNA gyrase} ightarrow 	ext{No DNA replication}$$

Question 11

Which of the following is a major reason why antimicrobial resistance develops when patients do not complete the full course of antibiotics?

Accepted Answer

Resistant microbes survive and multiply, leading to a population that is harder to treat.

Question 12

Which antibiotic is used to distinguish Streptococcus pyogenes from other 'Strep' bacteria due to its sensitivity?

Accepted Answer

Bacitracin

Question 13

Which equation best represents the action of penicillin on peptidoglycan synthesis?

Accepted Answer

$$	ext{Penicillin} + 	ext{Transpeptidase} ightarrow 	ext{No peptide cross-link}$$

Question 14

Which drug inhibits the synthesis of mycolic acid in the cell wall of Mycobacteria?

Accepted Answer

Isoniazid

Question 15

Which antibiotic is most likely to cause visual impairment as a side effect?

Accepted Answer

Ethambutol

Question 16

Which equation best represents the inhibition of bacterial RNA synthesis by rifamycins?

Accepted Answer

$$	ext{Rifamycin} + 	ext{RNA polymerase} ightarrow 	ext{No mRNA synthesis}$$

Question 17

Which of the following is a major side effect of aminoglycosides such as streptomycin?

Accepted Answer

Ototoxicity and nephrotoxicity

Question 18

Which class of antibiotics is most likely to be used as a topical preparation due to severe nephrotoxicity when used internally?

Accepted Answer

Bacitracin

Question 19

Which equation best represents the action of vancomycin on peptidoglycan synthesis?

Accepted Answer

$$	ext{Vancomycin} + 	ext{D-Ala-D-Ala} ightarrow 	ext{No peptide cross-link}$$

Controlling Microbial Growth in the Body: Antimicrobial Drugs

Study Guide - Practice Questions