Question 1

Which of the following best describes the contribution of Alexander Fleming to the field of antimicrobials?

Accepted Answer

He discovered penicillin, the first true antibiotic, by observing its effect on Staphylococcus bacteria.

Question 2

Which statement correctly distinguishes semisynthetic antimicrobials from antibiotics?

Accepted Answer

Antibiotics are modified in the lab to improve their efficacy, resulting in semisynthetic antimicrobials.

Question 3

The principle of selective toxicity is best described as:

Accepted Answer

The ability of a drug to target microbial structures or functions not found in host cells.

Question 4

Which of the following is NOT a mechanism by which antimicrobial drugs affect pathogens?

Accepted Answer

Enhancement of host immune response

Question 5

Which drug acts by inhibiting the synthesis of peptidoglycan in bacterial cell walls?

Accepted Answer

Penicillin

Question 6

Which of the following drugs interferes with protein synthesis by binding to the 30S ribosomal subunit?

Accepted Answer

Streptomycin

Question 7

Mupirocin inhibits protein synthesis by:

Accepted Answer

Inhibiting isoleucyl-tRNA synthetase, preventing isoleucine incorporation into proteins.

Question 8

Which of the following best describes the action of polymyxins?

Accepted Answer

They disrupt the cytoplasmic membrane of Gram-negative bacteria, leading to cell lysis.

Question 9

Sulfonamides act as competitive inhibitors in the synthesis of folic acid by:

Accepted Answer

Mimicking para-aminobenzoic acid (PABA) and blocking the enzyme dihydropteroate synthase.

Question 10

In the context of antimicrobial drugs, an 'analog' is best defined as:

Accepted Answer

A molecule that is structurally similar to a natural substrate and competes for binding to an enzyme.

Question 11

Which of the following antiviral drugs interferes with viral metabolism by inhibiting reverse transcriptase?

Accepted Answer

Zidovudine (AZT)

Question 12

Nucleotide and nucleoside analogs inhibit nucleic acid synthesis by:

Accepted Answer

Incorporating into DNA or RNA and causing chain termination or faulty base pairing.

Question 13

Which of the following best describes the action of attachment antagonists in antiviral therapy?

Accepted Answer

They prevent viruses from binding to host cell receptors, blocking entry.

Question 14

A broad-spectrum antimicrobial drug is more likely than a narrow-spectrum drug to:

Accepted Answer

Cause superinfections by disrupting normal microbiota.

Question 15

Which test determines the minimum concentration of an antimicrobial that inhibits visible growth of a microorganism?

Accepted Answer

Minimum inhibitory concentration (MIC) test

Question 16

Which route of administration provides the fastest and most reliable delivery of an antimicrobial drug to the bloodstream?

Accepted Answer

Intravenous

Question 17

Which of the following is NOT a main category of side effects associated with antimicrobial therapy?

Accepted Answer

Suppression of host immune response

Question 18

The therapeutic index (TI) of a drug is calculated as:

Accepted Answer

$$ TI = \frac{	ext{Toxic Dose}}{	ext{Therapeutic Dose}} $$

Question 19

How can populations of resistant microbes arise in a hospital setting?

Accepted Answer

By spontaneous mutation and selection pressure from antimicrobial use.

Question 20

R plasmids contribute to antimicrobial resistance by:

Accepted Answer

Carrying genes that encode enzymes capable of inactivating drugs.

Question 21

Which of the following is NOT a mechanism by which bacteria can be resistant to antimicrobial drugs?

Accepted Answer

Increased uptake of the drug

Ch 10 Antimicrobial Drugs: Mechanisms, Effectiveness, and Resistance

Study Guide - Practice Questions