Question 1

Which of the following best describes a virus?

Accepted Answer

A non-living infectious agent composed of nucleic acid and a protein coat

Question 2

What is the main reason RNA viruses mutate more rapidly than DNA viruses?

Accepted Answer

RNA-dependent RNA polymerases lack proofreading ability

Question 3

Which enzyme is required for single-stranded antisense RNA (ssRNA-) viruses to synthesize mRNA?

Accepted Answer

RNA-dependent RNA polymerase

Question 4

A virus that infects bacteria is called a:

Accepted Answer

Bacteriophage

Question 5

Which of the following statements about viral genomes is correct?

Accepted Answer

A single virus contains either DNA or RNA, but not both

Question 6

What is the function of reverse transcriptase in retroviruses?

Accepted Answer

It synthesizes DNA from an RNA template

Question 7

Which of the following best defines 'tropism' in virology?

Accepted Answer

The specificity of a virus for a particular host cell or tissue type

Question 8

Which process describes a gradual accumulation of mutations in the influenza virus, leading to seasonal epidemics?

Accepted Answer

Antigenic drift

Question 9

What is the medical importance of phage conversion?

Accepted Answer

It can result in bacteria acquiring new virulence factors

Question 10

Which of the following best describes a 'provirus'?

Accepted Answer

Viral DNA integrated into the host genome

Question 11

Which immunoassay technique is illustrated by latex beads coated with viral antigen to detect patient antibodies, as shown in the provided image?

Accepted Answer

Agglutination assay

Question 12

Why can't viral infections be treated with antibiotics?

Accepted Answer

Viruses lack cell walls targeted by antibiotics

Question 13

What does the RT-PCR test detect in the diagnosis of SARS-CoV-2 infection?

Accepted Answer

Viral RNA sequences

Question 14

Which of the following best defines 'selective toxicity' in antiviral drug development?

Accepted Answer

The drug specifically targets viral processes with minimal harm to host cells

Question 15

What is a prion?

Accepted Answer

A misfolded protein that can induce abnormal folding of normal proteins

Question 16

Diseases caused by prions are called spongiform encephalopathies because:

Accepted Answer

They cause the brain to develop sponge-like holes

Question 17

Which of the following is a limitation of immunoassays such as agglutination and PCR?

Accepted Answer

There is a seroconversion window where the infection may not be detected

Question 18

Which two retroviruses can form proviruses and persist in host cells for decades before causing leukemia or lymphoma?

Accepted Answer

HIV and HTLV

Question 19

What is the outcome of antigenic shift in influenza viruses?

Accepted Answer

Major changes in viral antigens leading to pandemics

Question 20

Which of the following best describes a plaque in a viral assay?

Accepted Answer

A clear zone where host cells have been lysed by viruses

Comprehensive Study Guide for Chapter 6: Viruses and Prions

Study Guide - Practice Questions