Question 1

Which of the following best describes the function of a viral capsid?

Accepted Answer

It is the protein coat that covers and protects the viral genome.

Question 2

A bacteriophage infects a bacterial cell and integrates its DNA into the host genome without immediately destroying the host. This process is best described as:

Accepted Answer

The lysogenic cycle

Question 3

Which of the following statements about viroids is correct?

Accepted Answer

Viroids are small, circular, single-stranded RNA molecules that infect plants.

Question 4

Which enzyme is responsible for synthesizing DNA from an RNA template in retroviruses?

Accepted Answer

Reverse transcriptase

Question 5

A virus with a positive-sense single-stranded RNA genome infects a host cell. What is the first step after entry for this virus to begin producing viral proteins?

Accepted Answer

The viral RNA is directly translated by host ribosomes.

Question 6

Which of the following best explains why prions are unique among infectious agents?

Accepted Answer

They are infectious proteins that lack nucleic acids.

Question 7

During the lytic cycle of a bacteriophage, which event occurs first?

Accepted Answer

The phage injects its DNA into the host cell.

Question 8

Which of the following is a key difference between the lytic and lysogenic cycles?

Accepted Answer

The lysogenic cycle involves integration of viral DNA into the host genome, while the lytic cycle results in immediate host cell lysis.

Question 9

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

Accepted Answer

It helps the virus enter host cells by fusing with the host membrane.

Question 10

A scientist is studying a virus that uses host cell machinery to replicate its genome and assemble new virions. Which of the following best describes this process?

Accepted Answer

The virus hijacks the host's replicative machinery to produce nucleic acids, proteins, and assemble new viruses.

Question 11

Which of the following is true about double-stranded DNA viruses?

Accepted Answer

They require the host nucleus to replicate their genomes during the S phase of the cell cycle.

Question 12

Which of the following best explains why retroviruses are unique among RNA viruses?

Accepted Answer

They reverse transcribe their RNA genome into DNA, which integrates into the host genome.

Question 13

A patient is diagnosed with a prion disease. Which of the following best describes the mechanism of prion propagation?

Accepted Answer

Prions induce misfolding of normal proteins into the infectious prion form.

Question 14

Which of the following steps is NOT part of the general viral replication cycle in animal cells?

Accepted Answer

Integration of viral DNA into the host genome is required for all animal viruses.

Question 15

Which of the following best describes the genome of a viroid?

Accepted Answer

Single-stranded, circular RNA

Question 16

A virus is found to have a genome that is complementary to the mRNA needed for protein synthesis. This virus is most likely a:

Accepted Answer

Negative-sense RNA virus

Question 17

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

Accepted Answer

Attachment, injection of DNA, synthesis of viral components, assembly, lysis

Question 18

Which of the following best explains why some animal viruses are able to fuse their envelope with the host cell membrane?

Accepted Answer

The viral envelope is derived from the host cell membrane and contains proteins that mediate fusion.

Question 19

Which of the following is a distinguishing feature of prions compared to viruses and viroids?

Accepted Answer

Prions lack nucleic acids entirely.

Question 20

A researcher observes that a virus can only infect certain types of cells in a host organism. This specificity is most likely due to:

Accepted Answer

The presence of specific receptors on the host cell surface that the virus recognizes.

Viruses: Structure, Replication, and Other Infectious Agents

Study Guide - Practice Questions

Study Guide - Flashcards