Question 1

Which of the following best describes a virus?

Accepted Answer

A non-cellular particle that contains a genome and requires a host cell to reproduce

Question 2

Which of the following is NOT a typical function of accessory proteins found in some viruses?

Accepted Answer

Synthesizing host cell ribosomes

Question 3

Which of the following statements about viral genomes is correct?

Accepted Answer

Most DNA viruses are double-stranded DNA, while most RNA viruses are single-stranded RNA

Question 4

A chemotherapeutic agent with high selective toxicity is preferred because:

Accepted Answer

It targets the pathogen without harming the host or beneficial microbes

Question 5

Which of the following best explains why viruses are not considered living organisms?

Accepted Answer

They cannot replicate without a host cell

Question 6

Which of the following is a correct match between antibiotic class and its primary target?

Accepted Answer

Beta-lactams: Cell wall synthesis

Question 7

A patient is prescribed an antibiotic that inhibits protein synthesis by binding to the 30S ribosomal subunit. Which class of antibiotics is most likely being used?

Accepted Answer

Aminoglycosides

Question 8

Which of the following mechanisms is NOT a common bacterial strategy for antibiotic resistance?

Accepted Answer

Increasing the permeability of the cell membrane to antibiotics

Question 9

The minimum inhibitory concentration (MIC) of an antibiotic is best defined as:

Accepted Answer

The lowest concentration of the drug that prevents visible growth of a microorganism

Question 10

Which of the following best describes the structure of a typical icosahedral virus?

Accepted Answer

A capsid with 20 triangular faces and 12 corners, efficiently approximating a sphere

Question 11

Which of the following is a correct sequence of steps in the general viral infection cycle?

Accepted Answer

Attachment → Penetration → Synthesis → Assembly → Release

Question 12

A bacteriophage is grown on a bacterial lawn and clear zones are observed. What do these clear zones (plaques) represent?

Accepted Answer

Areas where bacterial cells have been lysed by the phage

Question 13

Which of the following is a plausible reason why a narrow-spectrum antibiotic is preferred over a broad-spectrum antibiotic?

Accepted Answer

It reduces harm to beneficial microbes and lowers the risk of antibiotic resistance

Question 14

Which of the following best explains why not every virion is infective when calculating plaque-forming units (PFU)?

Accepted Answer

Some virions may be defective or unable to infect host cells

Question 15

A virus with a helical capsid structure is most likely to have which of the following shapes?

Accepted Answer

Rod-shaped (filamentous)

Question 16

Which of the following is a real-world example of a virus providing a benefit to its host?

Accepted Answer

Some plant viruses increase drought tolerance and survival during freezing

Question 17

Which of the following best describes the function of an efflux pump in antibiotic resistance?

Accepted Answer

It actively transports antibiotics out of the bacterial cell, reducing intracellular concentration

Question 18

A new antibiotic is found to inhibit the synthesis of peptidoglycan. Which type of bacteria would be most affected by this drug?

Accepted Answer

Gram-positive bacteria

Question 19

Which of the following best explains why the zone of inhibition is used to measure antibiotic effectiveness?

Accepted Answer

It indicates the area where bacterial growth is prevented by the antibiotic

Question 20

Which of the following is a correct statement about the diversity of viruses?

Accepted Answer

Viruses are highly diverse in their genome types and infection cycles

Virology and Antimicrobial Agents: Core Concepts for Microbiology

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