$$\text{Burst size} = \frac{\text{Number of virions released}}{\text{Number of infected cells}}$$

Question 1

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

Accepted Answer

They can only replicate by using the enzymes and organelles of a host cell.

Question 2

A virus with a segmented, single-stranded, negative-sense RNA genome is most likely classified in which family?

Accepted Answer

Orthomyxoviridae

Question 3

Which step in the lytic replication cycle of a bacteriophage is responsible for the destruction of the host cell?

Accepted Answer

Release

Question 4

What is the primary difference between the replication of +ssRNA viruses and -ssRNA viruses in animal cells?

Accepted Answer

+ssRNA viruses can act as mRNA and be directly translated, while -ssRNA viruses require synthesis of a complementary strand.

Question 5

Which of the following is a mechanism by which viruses can contribute to the development of cancer?

Accepted Answer

Viruses insert their genome into tumor suppressor genes, disrupting cell cycle control.

Question 6

Which enzyme is unique to retroviruses and is responsible for synthesizing DNA from an RNA template?

Accepted Answer

Reverse transcriptase

Question 7

A patient is diagnosed with a prion disease. Which of the following statements about prions is CORRECT?

Accepted Answer

Prions are infectious proteins that cause normal proteins to misfold into β-sheets.

Question 8

Which of the following best explains why enveloped viruses are generally more sensitive to environmental conditions than non-enveloped viruses?

Accepted Answer

Their phospholipid bilayer envelope is easily disrupted by detergents and drying.

Question 9

Which of the following is a correct sequence of events for the replication of HIV in a host cell?

Accepted Answer

Attachment → Entry → Integration → Synthesis → Assembly → Release

Question 10

Which of the following equations correctly represents the burst size in a lytic viral infection?

Accepted Answer

$$	ext{Burst size} = \frac{	ext{Number of virions released}}{	ext{Number of infected cells}}$$

Question 11

Which of the following is TRUE regarding viroids?

Accepted Answer

Viroids are small, circular pieces of ssRNA that infect plants and lack a protein capsid.

Question 12

A virus is found to have a double-stranded DNA genome, an envelope, and glycoprotein spikes. Which of the following viruses could it be?

Accepted Answer

Herpes simplex virus

Question 13

Which of the following best describes antigenic shift in influenza viruses?

Accepted Answer

A major change in surface glycoproteins due to gene reassortment between different viral strains.

Question 14

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

Accepted Answer

The lysogenic cycle involves integration of viral DNA into the host genome, allowing the virus to remain dormant.

Question 15

Which of the following is NOT a characteristic of prion diseases?

Accepted Answer

They are caused by infectious RNA molecules.

Question 16

Which of the following best explains why viruses are not considered living organisms?

Accepted Answer

They cannot carry out metabolism or reproduce independently.

Question 17

Which of the following is a correct statement about the replication of dsDNA animal viruses?

Accepted Answer

Viral genome replication occurs in the nucleus, and viral proteins are made in the cytoplasm.

Question 18

Which of the following viruses is associated with the development of Burkitt’s lymphoma?

Accepted Answer

Epstein-Barr virus

Question 19

Which of the following best describes the function of the viral envelope glycoproteins?

Accepted Answer

They facilitate attachment and entry into host cells by recognizing specific receptors.

Viruses, Viroids, and Prions: Structure, Replication, and Pathogenicity

Study Guide - Practice Questions