Question 1

Which of the following best explains why antibiotics are generally ineffective against viruses?

Accepted Answer

Viruses lack peptidoglycan cell walls, which are targeted by many antibiotics.

Question 2

A scientist is studying a virus with a protein coat, a lipid envelope, and glycoprotein spikes. What is the primary function of the spikes?

Accepted Answer

To attach to specific receptors on the host cell surface

Question 3

Which of the following statements correctly distinguishes between a naked virus and an enveloped virus?

Accepted Answer

A naked virus lacks a lipid envelope and is generally more resistant to environmental stress.

Question 4

A bacteriophage infects a bacterial cell and integrates its genome into the host chromosome. What is the integrated viral DNA called?

Accepted Answer

Prophage

Question 5

During the lytic cycle of a virulent bacteriophage, which of the following events occurs last?

Accepted Answer

Lysis of the host cell and release of new phage particles

Question 6

Which of the following best describes the difference between a prophage and a provirus?

Accepted Answer

A prophage is viral DNA integrated into a bacterial genome, while a provirus is viral DNA integrated into an animal cell genome.

Question 7

A patient receives an RNA vaccine for a viral infection. Which of the following best describes how this vaccine works?

Accepted Answer

It delivers mRNA encoding a viral protein, which is then produced by the host cells to stimulate an immune response.

Question 8

Which of the following best defines 'host range' in virology?

Accepted Answer

The spectrum of host species a virus can infect

Question 9

A virus is found to infect only liver cells in humans. This specificity is best described as:

Accepted Answer

Tissue tropism

Question 10

Which of the following is NOT a step in the replication cycle of an animal virus?

Accepted Answer

Binary fission

Question 11

A laboratory is attempting to identify an unknown virus. Which of the following is NOT a standard method for virus identification?

Accepted Answer

Gram staining

Question 12

Interferons are important in antiviral defense because they:

Accepted Answer

Induce the production of antiviral proteins in neighboring cells

Question 13

Which of the following antiviral drug mechanisms is correctly matched with its action?

Accepted Answer

Inhibition of viral reverse transcriptase prevents synthesis of viral DNA from RNA.

Question 14

A patient is given a subunit vaccine. Which of the following best describes this type of vaccine?

Accepted Answer

It contains purified viral proteins but no whole virus particles.

Question 15

Which of the following best describes the 'burst time' in the context of bacteriophage replication?

Accepted Answer

The time interval between phage attachment and release of new virions

Question 16

A temperate bacteriophage differs from a virulent bacteriophage in that it:

Accepted Answer

Can integrate its genome into the host chromosome and enter a lysogenic cycle

Question 17

Which of the following is a similarity between the lysogenic cycle of bacteriophages and the provirus state of animal viruses?

Accepted Answer

Both involve integration of viral genetic material into the host genome

Question 18

A researcher is testing a new antiviral drug that blocks viral uncoating. At which stage of the animal virus replication cycle would this drug act?

Accepted Answer

After penetration but before biosynthesis

Question 19

Which of the following best explains why RNA viruses tend to mutate more rapidly than DNA viruses?

Accepted Answer

RNA-dependent RNA polymerases lack proofreading activity

Question 20

A hospital outbreak is traced to a virus that can only infect humans and not other animals. This is an example of:

Accepted Answer

A narrow host range

Study Guide: Viruses and Prions (Microbiology Exam Prep)

Study Guide - Practice Questions