Question 1

Which of the following statements best describes the genetic material found in viruses?

Accepted Answer

Viruses contain either DNA or RNA, but never both.

Question 2

A scientist isolates a virus with a helical capsid and a phospholipid envelope. Which of the following is most likely true about this virus?

Accepted Answer

It is an animal virus that is more fragile outside the host cell.

Question 3

Which step in the lytic replication cycle of bacteriophages is responsible for the destruction of the host cell?

Accepted Answer

Release

Question 4

What is the primary reason why enveloped viruses are generally more sensitive to disinfectants than naked viruses?

Accepted Answer

Their envelope is derived from the host cell membrane and is easily disrupted.

Question 5

Which of the following best explains why lysogenic and latent viral infections are generally longer lasting than lytic infections?

Accepted Answer

The viral genome integrates into the host genome and can remain dormant for extended periods.

Question 6

A patient is diagnosed with a persistent viral infection that slowly progresses over years. Which of the following best describes this type of infection?

Accepted Answer

Chronic infection

Question 7

Which of the following is a unique property of prions compared to viruses and viroids?

Accepted Answer

They are composed solely of protein and lack nucleic acids.

Question 8

Which of the following best describes the process of antigenic shift in influenza viruses?

Accepted Answer

Major genetic reassortment when two different strains coinfect a host cell, leading to new viral subtypes.

Question 9

Which of the following antiviral drugs acts by inhibiting the release of influenza viruses from infected cells?

Accepted Answer

Oseltamivir

Question 10

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

Accepted Answer

Orthomyxoviridae

Question 11

Which of the following is a correct statement about the replication of retroviruses?

Accepted Answer

They use a DNA intermediate transcribed by reverse transcriptase to produce new viral genomes.

Question 12

Which of the following best describes the role of viral spikes (peplomers) in infection?

Accepted Answer

They facilitate attachment and entry into specific host cells.

Question 13

A patient presents with symptoms of a prion disease. Which of the following is the most likely mechanism of disease progression?

Accepted Answer

Conversion of normal cellular PrP to abnormal prion PrP with β-pleated sheets.

Question 14

Which of the following is a real-world example of lysogenic conversion providing new pathogenic properties to bacteria?

Accepted Answer

Corynebacterium diphtheriae producing diphtheria toxin after infection by a prophage

Question 15

Which of the following best explains why antiviral drugs are more difficult to develop than antibacterial drugs?

Accepted Answer

Viruses are obligate intracellular pathogens with fewer unique targets for selective toxicity.

Question 16

Which of the following is a property shared by both viroids and prions?

Accepted Answer

Both are acellular infectious agents.

Question 17

A virus infects only human respiratory epithelial cells and not other cell types. This specificity is best described as:

Accepted Answer

Narrow tropism

Question 18

Which of the following best describes the function of neuraminidase in the influenza virus life cycle?

Accepted Answer

It cleaves sialic acid to facilitate viral release from infected cells.

Question 19

Which of the following is the most effective method for destroying prions on contaminated medical equipment?

Accepted Answer

Incineration or autoclaving in concentrated sodium hydroxide

Question 20

Which of the following best describes the mechanism of action of nucleoside analog antiviral drugs?

Accepted Answer

They mimic normal nucleotides, causing premature termination of viral nucleic acid synthesis.

Viruses and Prions: Structure, Replication, and Clinical Relevance

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