Question 1

Which of the following statements best distinguishes viruses from bacteria?

Accepted Answer

Viruses are obligatory intracellular parasites that lack ribosomes and an ATP-generating mechanism, while bacteria can generate ATP and have ribosomes.

Question 2

A scientist is studying a virus that has a helical capsid, an envelope, and spikes. Which of the following viruses is most likely being studied?

Accepted Answer

Marburg virus

Question 3

Which of the following best explains why most viruses infect only specific types of cells in one host?

Accepted Answer

Viruses require specific host attachment sites and compatible cellular factors.

Question 4

During the lytic cycle of a T-even bacteriophage, which step immediately follows the biosynthesis of viral components?

Accepted Answer

Maturation

Question 5

A patient is diagnosed with a persistent viral infection. Which of the following is the most likely characteristic of this infection?

Accepted Answer

The virus is continuously released over a long period, often leading to fatal outcomes.

Question 6

Which laboratory method is most appropriate for quantifying the number of infectious bacteriophage particles in a sample?

Accepted Answer

Plaque assay, counting plaque-forming units (PFU)

Question 7

Which of the following best describes the process of specialized transduction?

Accepted Answer

A phage transfers specific bacterial genes adjacent to the prophage to another bacterium.

Question 8

Which of the following is a key difference between the multiplication of DNA-containing animal viruses and RNA-containing animal viruses?

Accepted Answer

DNA viruses use host cell DNA polymerase for replication, while RNA viruses use RNA-dependent RNA polymerase.

Question 9

A virus is found to cause cancer by integrating its genetic material into the host cell’s DNA. What is the term for the viral DNA once it is integrated?

Accepted Answer

Provirus

Question 10

Which of the following best explains how an RNA virus can cause cancer if it does not have DNA to insert into the host genome?

Accepted Answer

The RNA virus uses reverse transcriptase to synthesize DNA from its RNA genome, which then integrates into the host genome.

Question 11

Which of the following is a characteristic of prions but not viruses?

Accepted Answer

Are composed solely of protein and lack nucleic acids

Question 12

A researcher is using a continuous cell line to culture animal viruses. What is a major advantage of continuous cell lines over primary cell lines?

Accepted Answer

Continuous cell lines are derived from transformed cells and can be maintained indefinitely.

Question 13

Which of the following best describes the eclipse period in a one-step viral growth curve?

Accepted Answer

The period after viral entry but before new virions are detectable.

Question 14

Which of the following is an example of a latent viral infection?

Accepted Answer

Herpes simplex virus causing cold sores

Question 15

A patient is infected with a virus that is released from the host cell by budding. Which of the following is most likely true about this virus?

Accepted Answer

It acquires its envelope from the host cell plasma membrane.

Question 16

Which of the following best describes the role of spikes on the surface of some viruses?

Accepted Answer

They are used for attachment to host cells.

Question 17

A bacterium acquires the ability to produce a toxin only after infection by a lysogenic phage. What is this phenomenon called?

Accepted Answer

Phage conversion

Question 18

Which of the following is a correct statement about the host range of viruses?

Accepted Answer

A virus can infect only specific types of cells in one host, determined by attachment sites and cellular factors.

Question 19

Which of the following laboratory techniques would be most appropriate for the rapid identification of influenza virus in a patient sample?

Accepted Answer

Rapid antigen test or ELISA

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

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