Question 1

Which of the following best explains why viruses are classified as nonliving microbes?

Accepted Answer

They lack cellular structure and cannot carry out metabolic processes independently.

Question 2

Which viral structure is responsible for protecting the viral genome and is composed of protein subunits called capsomeres?

Accepted Answer

Capsid

Question 3

A virus with a helical capsid and a lipid envelope most likely enters a host cell by which mechanism?

Accepted Answer

Fusion with the host cell membrane

Question 4

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes can be composed of either DNA or RNA, and may be single- or double-stranded.

Question 5

Why do RNA viruses evolve more rapidly than DNA viruses?

Accepted Answer

RNA-dependent RNA polymerases lack proofreading ability, leading to higher mutation rates.

Question 6

Antigenic shift in influenza viruses can lead to which of the following outcomes?

Accepted Answer

Major genetic reassortment resulting in new viral strains with pandemic potential

Question 7

Which of the following is NOT a criterion used by the International Committee on the Taxonomy of Viruses (ICTV) to classify viruses?

Accepted Answer

Ability to cause disease in humans

Question 8

A virus that can infect both birds and humans is said to have a broad:

Accepted Answer

Host range

Question 9

Which of the following best describes the lysogenic replication cycle of a temperate bacteriophage?

Accepted Answer

The phage genome integrates into the host genome and is replicated along with it, potentially conferring new properties to the host.

Question 10

Which of the following is a medically important consequence of phage conversion?

Accepted Answer

It can confer new pathogenic properties to bacteria, such as toxin production.

Question 11

Which step in animal virus replication is unique to enveloped viruses compared to naked viruses?

Accepted Answer

Release by budding from the host cell membrane

Question 12

A patient experiences recurring cold sores caused by herpes simplex virus. This is an example of which type of infection?

Accepted Answer

Latent persistent infection

Question 13

Which of the following viruses is associated with the development of cancer in humans?

Accepted Answer

Human papillomavirus (HPV)

Question 14

Which laboratory method is commonly used to grow influenza virus for vaccine production?

Accepted Answer

Embryonated (fertilized) eggs

Question 15

A latex agglutination test for a viral infection is positive. What does this indicate?

Accepted Answer

Viral antigens or patient antibodies to the virus are present in the sample.

Question 16

Which antiviral drug mechanism is correctly matched with its target?

Accepted Answer

Rimantadine – blocks viral uncoating

Question 17

Which of the following statements about prions is TRUE?

Accepted Answer

Prions are infectious proteins that cause transmissible spongiform encephalopathies.

Question 18

A virus is described as having a segmented, single-stranded, negative-sense RNA genome. Which family does it most likely belong to?

Accepted Answer

Orthomyxoviridae

Question 19

Which of the following best describes the process of antigenic drift?

Accepted Answer

Gradual accumulation of mutations in viral genes encoding surface proteins

Question 20

Which of the following is a correct convention for naming a virus family according to ICTV rules?

Accepted Answer

Italicized with first letter capitalized, ending in 'viridae'

Viruses and Prions: Structure, Classification, Replication, and Clinical Aspects

Study Guide - Practice Questions