Question 1

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

Accepted Answer

They lack the cellular machinery for protein synthesis and must hijack a host cell to replicate.

Question 2

A scientist discovers a new virus with a helical capsid, an envelope, and a single-stranded negative-sense RNA genome. Which virus does this most closely resemble?

Accepted Answer

Rabies virus

Question 3

Which of the following statements about viral envelopes is TRUE?

Accepted Answer

The envelope contains glycoproteins that facilitate attachment to host cell receptors.

Question 4

Which of the following is a key function of the HIV Nef protein in immune evasion?

Accepted Answer

It removes MHC I from the cell surface, reducing cytotoxic T cell recognition.

Question 5

Which of the following best describes the process of generalized transduction?

Accepted Answer

A phage accidentally packages random fragments of bacterial DNA during the lytic cycle.

Question 6

Which of the following is NOT a universal characteristic of life, and thus not exhibited by viruses?

Accepted Answer

Metabolism

Question 7

A virus with an icosahedral, non-enveloped capsid and a double-stranded DNA genome is most likely to be which of the following?

Accepted Answer

Adenovirus

Question 8

Which of the following best explains why the CCR5-Δ32 mutation confers resistance to HIV infection?

Accepted Answer

It deletes a host cell receptor required for HIV entry, preventing infection.

Question 9

Which of the following is a correct sequence of events in the general viral replication cycle?

Accepted Answer

Attachment → Entry → Uncoating → Replication → Assembly → Release

Question 10

Which of the following best describes the role of the viral capsid?

Accepted Answer

It protects the viral genome and facilitates attachment to host cells.

Question 11

Which of the following is a major tradeoff for enveloped viruses compared to naked viruses?

Accepted Answer

Enveloped viruses are more fragile in the environment but can fuse with host membranes more easily.

Question 12

Which of the following statements about viral genomes is TRUE?

Accepted Answer

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

Question 13

Which of the following is a function of the influenza NS1 protein?

Accepted Answer

It sequesters viral dsRNA and blocks interferon signaling, suppressing host antiviral responses.

Question 14

Which of the following best describes the difference between the lytic and lysogenic cycles of bacteriophage infection?

Accepted Answer

The lytic cycle results in the destruction of the host cell, while the lysogenic cycle allows the phage genome to persist in the host without killing it.

Question 15

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

Accepted Answer

Prions are infectious proteins that lack nucleic acids.

Question 16

A virus is found to infect only neurons in the central nervous system of mammals. This is an example of:

Accepted Answer

Tissue tropism

Question 17

Which of the following best explains why viruses are not considered alive by most biologists?

Accepted Answer

They lack cellular organization, metabolism, and homeostasis.

Question 18

Which of the following is the correct formula for the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} \xrightarrow{	ext{transcription}} 	ext{RNA} \xrightarrow{	ext{translation}} 	ext{Protein}$$

Question 19

Which of the following best describes the process by which a viroid causes disease in plants?

Accepted Answer

Viroid RNA hijacks the host's RNA silencing machinery, disrupting normal gene expression.

Question 20

Which of the following is a key determinant of a virus's host range?

Accepted Answer

The presence of compatible host cell receptors for viral attachment proteins.

Viruses, Viroids, and Prions: Foundations of Viral Biology

Study Guide - Practice Questions

Study Guide - Flashcards