Question 1

Which of the following is a characteristic shared by all viruses?

Accepted Answer

They possess a protein capsid that encloses their genetic material.

Question 2

Which of the following best distinguishes viruses from bacteria?

Accepted Answer

Viruses lack cellular structure and metabolic machinery, while bacteria are cellular and metabolically active.

Question 3

What is the primary function of viral spikes?

Accepted Answer

To facilitate attachment to specific host cell receptors.

Question 4

When do viruses acquire their envelope, and what is its origin?

Accepted Answer

During release from the host cell, by budding through the host cell membrane.

Question 5

Which of the following correctly compares the entry and exit of enveloped versus non-enveloped viruses?

Accepted Answer

Enveloped viruses enter by fusion or endocytosis and exit by budding, while non-enveloped viruses enter by endocytosis and exit by lysis.

Question 6

Which enzyme is responsible for integrating the HIV genome into the host DNA?

Accepted Answer

Integrase

Question 7

Acyclovir is an example of a nucleoside reverse transcriptase inhibitor (NRTI). What is its mechanism of action?

Accepted Answer

It mimics nucleosides and causes premature chain termination during viral DNA synthesis.

Question 8

Which of the following best describes the lytic cycle of a bacteriophage?

Accepted Answer

The phage replicates immediately, leading to host cell lysis and release of new phages.

Question 9

What is a prophage?

Accepted Answer

A phage genome integrated into the bacterial chromosome.

Question 10

Which of the following best describes specialized transduction?

Accepted Answer

Only specific bacterial genes adjacent to the prophage are transferred by a lysogenic phage.

Question 11

Which of the following is a key reason why the composition of the influenza vaccine changes each year?

Accepted Answer

The flu virus undergoes frequent antigenic drift and shift, altering its surface proteins.

Question 12

Which mechanism allows influenza viruses to cause pandemics by creating new viral subtypes?

Accepted Answer

Antigenic shift

Question 13

Which of the following is a major health problem caused by persistent infection with human papillomavirus (HPV)?

Accepted Answer

Cervical cancer

Question 14

A patient is diagnosed with chronic hepatitis B infection. Which of the following best describes this type of infection?

Accepted Answer

The virus persists in the liver, potentially leading to cirrhosis or liver cancer.

Question 15

Why is Burkitt’s lymphoma more common in Africa than in other regions?

Accepted Answer

Co-infection with Epstein-Barr virus and malaria increases the risk.

Question 16

Which of the following best distinguishes a latent viral infection from a persistent viral infection?

Accepted Answer

Latent infections involve periods of dormancy with possible reactivation, while persistent infections involve continuous viral presence and replication.

Question 17

A patient presents with symptoms of mononucleosis. Which virus is most likely responsible, and how is it transmitted?

Accepted Answer

Epstein-Barr virus; transmitted by saliva.

Question 18

Which of the following best describes phage conversion?

Accepted Answer

A bacterium acquires new genetic traits due to the presence of a prophage.

Question 19

A virologist is studying a new virus that lacks an envelope and is released from host cells by lysis. Which of the following is most likely true about this virus?

Accepted Answer

It is a non-enveloped virus that exits by rupturing the host cell.

Question 20

Which of the following equations best represents the process of reverse transcription in retroviruses such as HIV?

Accepted Answer

$$RNA \rightarrow DNA \rightarrow Protein$$

Comprehensive Study Guide for Chapter 13: Viruses (Microbiology)

Guida di studio - Domande di pratica

Study guide - Flashcard