Question 1

Which of the following statements best explains why viruses are considered obligate intracellular pathogens?

Accepted Answer

They require host cell energy and machinery to replicate because they lack the necessary components for independent life.

Question 2

A scientist is studying a virus with a helical capsid, an RNA genome, and a lipid envelope. Which of the following best describes how this virus is likely to enter an animal host cell?

Accepted Answer

By fusion of the viral envelope with the host cell membrane.

Question 3

Which of the following best describes antigenic drift in influenza viruses?

Accepted Answer

A spontaneous mutation causing minor changes in HA and NA spikes, leading to reduced immunity in the host.

Question 4

Which of the following is a unique feature of prions compared to viruses?

Accepted Answer

They are infectious proteins with no genetic material and do not replicate.

Question 5

A patient is diagnosed with a persistent viral infection that is characterized by periods of dormancy and flare-ups. Which virus family is most likely responsible for this infection?

Accepted Answer

Herpesviridae

Question 6

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

Accepted Answer

RNA polymerases lack proofreading capabilities, leading to higher mutation rates.

Question 7

A laboratory is using a plaque assay to quantify bacteriophages in a sample. What does each plaque on the bacterial lawn represent?

Accepted Answer

A single bacteriophage that infected and lysed bacterial cells.

Question 8

Which of the following antiviral drugs acts by mimicking normal nucleotides and terminating viral nucleic acid replication?

Accepted Answer

Acyclovir

Question 9

A virus is classified as a member of the family Herpesviridae. According to viral taxonomy conventions, which of the following is the correct way to write the family name?

Accepted Answer

Herpesviridae

Question 10

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

Accepted Answer

A major genetic reassortment when two different strains coinfect a host cell, potentially leading to a pandemic.

Question 11

Which of the following is a reason why developing antiviral drugs is more challenging than developing antibacterial drugs?

Accepted Answer

Viruses are obligate intracellular pathogens and share many processes with host cells, making selective toxicity difficult.

Question 12

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

Accepted Answer

They are glycoprotein extensions that help viruses attach and gain entry to specific host cells.

Question 13

A virus with a segmented RNA genome infects a host cell already infected with a different strain of the same virus. What is the most likely outcome?

Accepted Answer

Genetic reassortment may occur, producing a new viral strain with mixed genome segments.

Question 14

Which of the following viruses is associated with the development of cancer due to chronic inflammation rather than direct integration of viral genes into the host genome?

Accepted Answer

Hepatitis B virus

Question 15

Which of the following best describes the difference between a naked virus and an enveloped virus?

Accepted Answer

Enveloped viruses acquire their envelope from the host cell membrane during budding, while naked viruses lack an envelope and are released by cell lysis.

Question 16

Which of the following is a correct statement about the host range and tropism of viruses?

Accepted Answer

Host range refers to the collection of species a virus can infect, while tropism refers to the specific tissues or cells within a host.

Question 17

Which of the following laboratory methods is most sensitive for detecting the presence of a specific viral genome in a clinical sample?

Accepted Answer

Polymerase chain reaction (PCR)

Question 18

A patient receives a post-exposure prophylaxis treatment after a potential rabies exposure. What is the mechanism of this treatment?

Accepted Answer

It provides laboratory-prepared antibodies that prevent the virus from binding and entering host cells.

Question 19

Which of the following best explains why vaccines are a critical tool in the prevention of viral diseases?

Accepted Answer

Vaccines train the immune system to recognize and respond to specific viruses, limiting infection.

Viruses and Prions: Structure, Replication, and Clinical Relevance

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