Question 1

Which of the following is a key argument against considering viruses as living organisms?

Accepted Answer

Viruses cannot carry out metabolic processes independently.

Question 2

During the lytic cycle of a bacteriophage, which step immediately follows the replication of the viral genome?

Accepted Answer

Assembly of new virus particles

Question 3

A virus with a negative-sense single-stranded RNA genome must bring which enzyme with it to successfully replicate in a host cell?

Accepted Answer

RNA replicase

Question 4

Which of the following best describes the difference between the lytic and lysogenic (latency) cycles?

Accepted Answer

The lytic cycle leads to rapid production and release of new virions, while the lysogenic cycle involves viral genome integration and dormancy.

Question 5

Which of the following is a real-world example of a virus using a specific host cell receptor for entry?

Accepted Answer

HIV binding to the CD4 receptor on T cells

Question 6

A virus with a (+)ssRNA genome can be directly translated by host ribosomes. What is the first step in the replication of its genome?

Accepted Answer

Synthesis of a complementary (-)ssRNA strand

Question 7

Which of the following best explains why antiviral drugs targeting viral protease are effective against HIV?

Accepted Answer

Protease inhibitors prevent the cleavage of viral polypeptides, blocking the formation of functional viral proteins.

Question 8

Which type of vaccine contains only small pieces of the virus, such as proteins, and not the whole virus?

Accepted Answer

Subunit vaccine

Question 9

A scientist discovers a new virus with a double-stranded DNA genome. Which host enzyme is most likely required for the virus to replicate its genome?

Accepted Answer

Host DNA polymerase

Question 10

Which of the following best describes the process of viral budding?

Accepted Answer

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

Question 11

Which of the following equations best represents the exponential increase in the number of virions during the lytic cycle?

Accepted Answer

$$N = N_0$ e$$^{kt}$$

Question 12

A patient is infected with a retrovirus. Which enzyme is essential for the virus to convert its RNA genome into DNA?

Accepted Answer

Reverse transcriptase

Question 13

Which of the following is a plausible reason for a virus to enter a lysogenic (latent) cycle instead of immediately entering the lytic cycle?

Accepted Answer

To avoid detection by the host immune system during unfavorable conditions

Question 14

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes can be linear or circular, and composed of DNA or RNA.

Question 15

Which of the following best explains how mRNA vaccines (such as those for SARS-CoV-2) work?

Accepted Answer

They deliver mRNA encoding a viral protein, which is translated by host ribosomes to stimulate an immune response.

Question 16

Which of the following is a common misconception about the treatment of viral infections?

Accepted Answer

Antibiotics are effective against viruses.

Question 17

A virus with an ambisense RNA genome will require which of the following for gene expression?

Accepted Answer

Both host ribosomes and viral RNA replicase

Question 18

Which of the following best describes the role of vaccines in preventing viral infections?

Accepted Answer

Vaccines stimulate the production of antibodies and memory cells against viral antigens.

Question 19

Which of the following is a plausible reason why enveloped viruses are often more sensitive to environmental conditions than non-enveloped viruses?

Accepted Answer

Their lipid envelope can be disrupted by detergents and drying.

Question 20

Which of the following steps is unique to retroviruses during their replication cycle?

Accepted Answer

Synthesis of DNA from an RNA template

Viruses: Structure, Life Cycles, and Control

Study Guide - Practice Questions