Question 1

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

Accepted Answer

They are unable to reproduce independently outside of a host cell.

Question 2

A scientist is studying a virus that infects only E. coli bacteria but not other bacterial species or animal cells. This specificity is best described as:

Accepted Answer

Host range

Question 3

Which of the following statements about bacteriophages is correct?

Accepted Answer

They are viruses that specifically infect bacteria.

Question 4

A virus with a helical capsid structure would most likely appear as:

Accepted Answer

A rod-shaped or filamentous particle

Question 5

Which of the following is NOT a component of all viruses?

Accepted Answer

Envelope

Question 6

A patient is infected with an influenza virus that has undergone a major change in its HA and NA spikes, resulting in a new subtype. This process is known as:

Accepted Answer

Antigenic shift

Question 7

Which of the following best describes a latent viral infection?

Accepted Answer

The virus remains dormant in the host cell and can reactivate later.

Question 8

A virus is described as 'naked.' What does this mean about its structure?

Accepted Answer

It lacks a lipid envelope and consists only of a nucleic acid and capsid.

Question 9

Which of the following is a correct pairing of viral taxonomy endings?

Accepted Answer

Family: -viridae; Genus: -virus

Question 10

A laboratory is attempting to grow a newly discovered animal virus. Which of the following methods would be most appropriate for initial isolation and propagation?

Accepted Answer

Inoculation into embryonated eggs

Question 11

Why can't Koch's postulates always be used to identify viral diseases?

Accepted Answer

Viruses require living host cells for replication and cannot be grown in pure culture.

Question 12

A patient is exposed to a known viral pathogen and is immediately given a treatment to prevent infection. This intervention is best described as:

Accepted Answer

Post exposure prophylaxis

Question 13

Which of the following best describes the function of interferons in viral infections?

Accepted Answer

They are host proteins that inhibit viral replication.

Question 14

A virus integrates its genome into the host cell's DNA and remains there, sometimes for years, without producing new virions. This integrated viral DNA is called:

Accepted Answer

Provirus

Question 15

Which of the following best describes the process of antigenic drift?

Accepted Answer

Gradual accumulation of mutations in viral genes encoding surface proteins

Question 16

A latex agglutination test is used in a clinical laboratory to detect viral antigens. What is the principle behind this test?

Accepted Answer

Antibodies attached to latex beads bind to viral antigens, causing visible clumping.

Question 17

Which of the following is a plausible reason why detection and enumeration of viruses is more complicated than for bacteria?

Accepted Answer

Viruses cannot multiply outside of a host cell.

Question 18

A patient is diagnosed with a persistent viral infection. Which of the following best characterizes this type of infection?

Accepted Answer

The virus remains in the host for long periods, often with ongoing low-level replication.

Question 19

Which of the following is a correct description of a nucleoside analog used in antiviral therapy?

Accepted Answer

A molecule that mimics a natural nucleoside and inhibits viral nucleic acid synthesis

Question 20

A virus is described as oncogenic. What does this mean?

Accepted Answer

It has the potential to cause cancer in the host.

Microbiology Study Guide: Viruses and Prions (Chapter 6)

Study Guide - Practice Questions

Study Guide - Flashcards