$$\text{dsDNA} \rightarrow \text{mRNA} \rightarrow \text{protein}$$

Question 1

Which of the following best describes a virion?

Accepted Answer

A single infectious virus particle containing genetic material and capable of infecting host cells.

Question 2

Which statement correctly distinguishes viruses from cellular living organisms?

Accepted Answer

Viruses are acellular and obligate intracellular pathogens, while cellular organisms are made of cells and can reproduce independently.

Question 3

Which of the following is NOT a function of viral spike proteins?

Accepted Answer

Encoding viral genome replication enzymes.

Question 4

A virus with a helical capsid and an envelope would most likely appear as:

Accepted Answer

A rod-shaped structure surrounded by a lipid membrane.

Question 5

Which of the following viral structures is unique to bacteriophages and not found in animal viruses?

Accepted Answer

Tail fibers used for attachment to bacterial cells.

Question 6

According to the Baltimore classification, which type of viral genome requires reverse transcription to produce mRNA?

Accepted Answer

Retrovirus (RNA genome with reverse transcriptase)

Question 7

Most viruses have fewer than 300 genes. Which of the following best explains why viral genomes are so small compared to cellular genomes?

Accepted Answer

Viruses rely on host cell machinery for most functions, so they only encode essential proteins for replication and structure.

Question 8

Which of the following shapes is characteristic of a naked virus with an icosahedral capsid?

Accepted Answer

A polyhedral structure with 20 triangular faces.

Question 9

Which of the following is a correct sequence for protein synthesis in a double-stranded DNA virus, according to the Baltimore classification?

Accepted Answer

$$	ext{dsDNA} ightarrow 	ext{mRNA} ightarrow 	ext{protein}$$

Question 10

Which of the following best describes the role of the capsid in a virus?

Accepted Answer

Protects the viral genome and aids in delivery to host cells.

Question 11

A scientist is studying a virus that can only be visualized using a transmission electron microscope. What does this indicate about the virus?

Accepted Answer

It is submicroscopic and smaller than bacteria.

Question 12

Which of the following viral genes is LEAST likely to be encoded by a typical viral genome?

Accepted Answer

Genes for host cell metabolic enzymes.

Question 13

Which of the following is a correct definition of virology?

Accepted Answer

The study of viruses.

Question 14

Which of the following is true about the epidemiology of viral diseases?

Accepted Answer

It focuses on how diseases affect whole communities, including patterns of outbreaks and transmission.

Question 15

Which of the following viruses is an example of a recent epidemic mentioned in the study materials?

Accepted Answer

SARS-CoV-2 (causes COVID-19)

Question 16

A virus with a spherical envelope and spike proteins is most likely to:

Accepted Answer

Use its spike proteins to attach to host cell receptors and enter the cell.

Question 17

Which of the following viral genome types requires the most steps to produce proteins, compared to cellular DNA?

Accepted Answer

Retrovirus (RNA genome with reverse transcription)

Question 18

Which of the following is a correct description of a helical virus?

Accepted Answer

A virus with a capsid arranged in a spiral around its nucleic acid.

Question 19

Which of the following is NOT a characteristic of viruses?

Accepted Answer

Ability to reproduce independently outside host cells.

Question 20

Which of the following best describes the Baltimore classification system for viruses?

Accepted Answer

It categorizes viruses based on their genome type and the pathway used to synthesize mRNA.

Chapter 19: Viruses – Structure, Function, and Genomes

Study Guide - Practice Questions