Question 1

Which of the following statements best describes the genetic material of viruses?

Accepted Answer

Viruses may contain either DNA or RNA, which can be single- or double-stranded, linear or circular.

Question 2

A scientist discovers a new virus that infects only a specific type of liver cell in humans. What is the most likely explanation for this specificity?

Accepted Answer

The virus's surface proteins have an affinity for complementary proteins on the liver cell membrane.

Question 3

Which of the following best describes the difference between the extracellular and intracellular states of a virus?

Accepted Answer

In the extracellular state, the virus is called a virion and has a capsid; in the intracellular state, the capsid is removed and only the nucleic acid remains.

Question 4

Which of the following is NOT a basic shape used to classify viruses?

Accepted Answer

Cylindrical

Question 5

During the lytic replication cycle of a bacteriophage, which stage immediately follows 'entry'?

Accepted Answer

Synthesis

Question 6

Which of the following equations best represents the burst size in a lytic cycle experiment, where $$N_{final} is $$the number of virions after lysis and $$N_{initial} is $$the number of infected cells?

Accepted Answer

$$Burst\ Size = \frac{N_{final}}{N_{initial}}$$

Question 7

Which of the following is a key difference between the replication of animal viruses and bacteriophages?

Accepted Answer

Animal viruses may enter host cells by membrane fusion or endocytosis, while bacteriophages inject their genome into the host.

Question 8

A virus is found to have a phospholipid envelope with glycoprotein spikes. Which of the following is TRUE about this virus?

Accepted Answer

Its envelope is acquired from the host cell during replication or release.

Question 9

Which of the following best explains why enveloped viruses are generally more fragile than naked viruses?

Accepted Answer

Their phospholipid bilayer envelope is sensitive to desiccation, heat, and detergents.

Question 10

Which of the following mechanisms is used by retroviruses to replicate their genomes?

Accepted Answer

They use a DNA intermediary transcribed by reverse transcriptase.

Question 11

Which of the following is a possible outcome of lysogenic conversion in bacteria?

Accepted Answer

The bacterium acquires new traits, such as toxin production, due to phage genes.

Question 12

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

Accepted Answer

Attachment → Entry → Synthesis → Assembly → Release

Question 13

Which of the following best describes the role of protooncogenes in cells?

Accepted Answer

They promote normal cell growth and division.

Question 14

A patient is diagnosed with cervical cancer linked to a viral infection. Which of the following mechanisms could explain how the virus contributed to cancer development?

Accepted Answer

The virus inserted its genome near a protooncogene, causing uncontrolled cell division.

Question 15

Which of the following is NOT a criterion used to classify viruses?

Accepted Answer

Ability to photosynthesize

Question 16

Which of the following statements about viral latency in animal cells is correct?

Accepted Answer

A provirus incorporated into host DNA is permanent and may remain dormant for years.

Question 17

Which of the following best describes the process of budding in enveloped viruses?

Accepted Answer

The virus acquires its envelope from the host cell membrane as it exits.

Question 18

Which of the following is a real-world example of a cancer caused by a virus?

Accepted Answer

Kaposi’s sarcoma

Question 19

Which of the following statements about the viral envelope is FALSE?

Accepted Answer

It always contains host DNA.

Characterizing and Classifying Viruses, Viroids, and Prions: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards