Question 1

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

Accepted Answer

They can only replicate inside living host cells because they lack the necessary cellular machinery for independent reproduction.

Question 2

A virus with a helical capsid structure is most likely to appear as:

Accepted Answer

A hollow tube with the viral genome coiled inside.

Question 3

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, leading to higher mutation rates.

Question 4

A patient is diagnosed with influenza. Which process is most responsible for the emergence of a new, highly virulent influenza strain capable of causing a pandemic?

Accepted Answer

Antigenic shift, which results from reassortment of viral genomes when two different strains coinfect a host cell.

Question 5

Which of the following is a correct sequence of steps in the lytic replication cycle of a bacteriophage?

Accepted Answer

Attachment → Penetration → Replication → Assembly → Release

Question 6

Which of the following best describes the process of phage conversion?

Accepted Answer

A bacterium acquires new pathogenic traits due to the presence of a prophage.

Question 7

Which of the following viruses is most likely to be released from a host cell by budding?

Accepted Answer

An enveloped animal virus

Question 8

A virus with a single-stranded positive-sense RNA genome ($$ssRNA^+) $$can:

Accepted Answer

Be directly translated by host ribosomes to produce viral proteins.

Question 9

Which of the following laboratory methods is most appropriate for quantifying the number of infectious bacteriophages in a sample?

Accepted Answer

Plaque assay, which measures plaque-forming units (PFUs) per milliliter.

Question 10

Which of the following best explains why ELISA tests may fail to detect a recent viral infection?

Accepted Answer

The patient has not yet produced detectable levels of antibodies (seroconversion window).

Question 11

A patient presents with recurring cold sores. Which type of viral infection is most likely responsible for the intermittent flare-ups?

Accepted Answer

Latent persistent infection

Question 12

Which of the following antiviral drugs works by inhibiting the release of influenza virions from the host cell surface?

Accepted Answer

Oseltamivir (Tamiflu)

Question 13

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

Accepted Answer

Prions are infectious proteins that lack genetic material.

Question 14

A virus is classified as a member of the Herpesviridae family. Which of the following properties is most likely used in its classification?

Accepted Answer

Type of nucleic acid, capsid symmetry, presence of envelope, and genome architecture.

Question 15

Which of the following best describes the host range of a virus?

Accepted Answer

The collection of species that a virus can infect.

Question 16

Which of the following is a medically important DNA virus family that can cause cervical cancer?

Accepted Answer

Papillomaviridae

Question 17

A researcher is studying a virus with a segmented, double-stranded RNA genome. Which family does this virus most likely belong to?

Accepted Answer

Reoviridae

Question 18

Which of the following best explains why nucleoside analogs are effective antiviral drugs?

Accepted Answer

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

Question 19

A virus is found to integrate its genome into the host cell DNA and remain dormant for years before reactivating. Which of the following terms best describes this viral strategy?

Accepted Answer

Latent persistent infection

Question 20

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

Accepted Answer

Viruses have fewer chemically distinct targets because they rely on host cell machinery for replication.

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

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