Question 1

Which of the following best describes a latent animal virus infection?

Accepted Answer

The virus remains dormant in host cells for years with no viral activity.

Question 2

Which process is responsible for the permanent integration of a provirus into host DNA?

Accepted Answer

Insertion of viral DNA into the host genome.

Question 3

A patient is diagnosed with a persistent viral infection. Which of the following best describes the pattern of virion abundance over time in this type of infection?

Accepted Answer

Virion abundance gradually increases and remains elevated over a prolonged period.

Question 4

Which of the following is NOT a known mechanism by which viruses can contribute to cancer development?

Accepted Answer

Viruses directly destroy all host cell DNA, preventing cell division.

Question 5

Which of the following human cancers is NOT known to be caused by viruses?

Accepted Answer

Lung cancer caused by tobacco smoke.

Question 6

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that cause other proteins to misfold.

Question 7

A researcher is culturing viruses in the laboratory. Which of the following is NOT a suitable medium for viral growth?

Accepted Answer

Standard nutrient agar plates without host cells.

Question 8

Which of the following best explains why prion diseases are difficult to treat?

Accepted Answer

Prions are resistant to standard sterilization and are not destroyed by most treatments.

Question 9

Which of the following equations best represents the exponential increase in virion abundance during the release phase of a persistent infection?

Accepted Answer

$$N(t) = N_0$ e$$^{kt}$$

Question 10

Which of the following is a key difference between viroids and viruses?

Accepted Answer

Viroids lack a capsid and do not code for proteins.

Question 11

A virus is found to cause uncontrolled cell division in a host. Which of the following genetic events is most likely responsible?

Accepted Answer

Activation of an oncogene by viral insertion.

Question 12

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

Accepted Answer

Viral proteins and capsids are enveloped by the host membrane and released by exocytosis.

Question 13

Which of the following is a characteristic of malignant tumors but NOT benign tumors?

Accepted Answer

Ability to metastasize to other tissues.

Question 14

Which of the following best explains why the integration of a provirus into host DNA is considered permanent?

Accepted Answer

The viral DNA becomes part of the host genome and is replicated with it.

Question 15

Which of the following is a correct statement about the structure of prion proteins?

Accepted Answer

Normal prion proteins have $$\alpha-$$helices, while infectious prions have $$\beta-$$sheets.

Question 16

A viroid infects a plant cell. Which of the following best describes its mechanism of pathogenicity?

Accepted Answer

It binds to complementary plant RNA, forming double-stranded RNA that is degraded by the cell.

Question 17

Which of the following is the most effective method for destroying prions in contaminated surgical instruments?

Accepted Answer

Incineration or autoclaving in concentrated sodium hydroxide.

Question 18

Which of the following best explains why viruses cannot be grown in standard microbiological media?

Accepted Answer

Viruses require living host cells for replication.

Question 19

A patient presents with symptoms of Creutzfeldt-Jakob disease (CJD). Which of the following is the most likely cause?

Accepted Answer

Ingestion or transplantation of prion-contaminated tissue.

Question 20

Which of the following best describes the role of tumor suppressor genes in normal cells?

Accepted Answer

They inhibit uncontrolled cell division.

Animal Viruses: Replication, Latency, Cancer, and Prions

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