Question 1

Which of the following best describes a virion?

Accepted Answer

The acellular form of a virus that facilitates transmission between host cells

Question 2

What is the primary function of the capsid in a virus?

Accepted Answer

To surround and protect the viral genome

Question 3

Which statement about viral genomes is correct?

Accepted Answer

Viral genomes can be either DNA or RNA, and may be linear or circular

Question 4

A virus with helical symmetry is most likely to have which of the following shapes?

Accepted Answer

Rod-shaped

Question 5

Which of the following is a subunit of the viral capsid?

Accepted Answer

Capsomere

Question 6

Enveloped viruses differ from naked viruses in that they:

Accepted Answer

Possess a lipoprotein membrane surrounding the nucleocapsid

Question 7

Which enzyme is commonly found in some virions and is critical for infectivity by cleaving glycosidic bonds?

Accepted Answer

Neuraminidase

Question 8

A bacteriophage infects E. coli and enters the lysogenic cycle. What is a possible outcome?

Accepted Answer

Replication of the phage genome in tandem with the host genome without killing the host

Question 9

Which of the following best explains why most viruses are smaller than prokaryotic cells?

Accepted Answer

Viruses lack metabolic machinery and only carry essential genetic material for infection

Question 10

During the viral replication cycle, what does the 'burst size' refer to?

Accepted Answer

The number of virions released per infected cell

Question 11

Which of the following is a correct sequence for the steps in the one-step growth curve of a bacterial virus?

Accepted Answer

Attachment → Eclipse → Maturation → Release

Question 12

A viral plaque assay is used to:

Accepted Answer

Quantify the number of infectious virus particles in a sample

Question 13

Which of the following is true regarding the attachment of a virion to a host cell?

Accepted Answer

It requires complementary receptors on the surface of the susceptible host and the infecting virus

Question 14

Which of the following best describes the role of envelope proteins in animal viruses?

Accepted Answer

They attach to and infect animal host cells

Question 15

Which symmetry is exhibited by human papillomavirus?

Accepted Answer

Icosahedral symmetry

Question 16

Which of the following is a plausible consequence of lysogenic conversion in bacteria?

Accepted Answer

Acquisition of new virulence factors

Question 17

Which process allows enveloped animal viruses to exit their host cell?

Accepted Answer

Budding, acquiring part of the cytoplasmic membrane as an envelope

Question 18

A virus is found to have a genome composed of single-stranded RNA. Which of the following is a possible classification for this virus?

Accepted Answer

ssRNA virus

Question 19

Which of the following best explains why different tissues/organs are infected by different animal viruses?

Accepted Answer

Different tissues/organs express different surface proteins that act as viral receptors

Question 20

Which of the following equations correctly represents the calculation of virus titer in a plaque assay?

Accepted Answer

$$ 	ext{Virus Titer} = \frac{	ext{Number of Plaques}}{	ext{Volume of Sample (mL)}} $$

Introduction to Viruses: Structure, Genomes, and Symmetry

Study Guide - Practice Questions