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

Ebola 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 penetration?

Accepted Answer

Biosynthesis

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 is a correct description of the biosynthesis of RNA viruses?

Accepted Answer

RNA viruses use RNA-dependent RNA polymerase in the cytoplasm for genome replication.

Question 8

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 genetic material in this state?

Accepted Answer

Provirus

Question 9

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 10

Which of the following is a key feature of prions that distinguishes them from viruses?

Accepted Answer

Prions are infectious proteins without nucleic acids.

Question 11

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 12

Which of the following best explains why influenza pandemics can occur due to antigenic shift?

Accepted Answer

Antigenic shift occurs when viral genes from different species mix, creating a new virus capable of infecting humans.

Question 13

Which of the following is a real-world example of phage conversion?

Accepted Answer

Corynebacterium diphtheriae produces diphtheria toxin only when infected by a lysogenic phage.

Question 14

Which of the following steps is unique to the multiplication of animal viruses compared to bacteriophages?

Accepted Answer

Uncoating of the viral nucleic acid

Question 15

A patient presents with cold sores that recur during periods of stress. Which type of infection is this, and what is the causative virus?

Accepted Answer

Latent infection; Herpes simplex virus (HHV-1)

Question 16

Which of the following best describes the function of viral spikes?

Accepted Answer

They are projections made of carbohydrate and protein used for attachment to host cells.

Question 17

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

Accepted Answer

Rapid antigen test or ELISA

Question 18

Which of the following is a correct statement about the replication of retroviruses?

Accepted Answer

Retroviruses use reverse transcriptase to produce DNA from their RNA genome, which integrates into the host chromosome as a provirus.

Question 19

A patient is diagnosed with subacute sclerosing panencephalitis (SSPE) years after a measles infection. This is an example of which type of viral infection?

Accepted Answer

Persistent infection

Question 20

Which of the following best explains how a protein can be infectious, as in prion diseases?

Accepted Answer

The misfolded prion protein induces normal proteins to adopt the infectious conformation, leading to disease.

Chapter 13

Guida di studio - Domande di pratica

Study guide - Flashcard