Question 1

Which of the following best describes the main difference between the lytic and lysogenic replication pathways of bacteriophages?

Accepted Answer

Lytic replication results in immediate destruction of the host cell, while lysogenic replication allows the phage genome to integrate into the host genome and persist without killing the cell.

Question 2

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

Accepted Answer

Replication (synthesis)

Question 3

What is phage conversion, and why is it medically important?

Accepted Answer

It is when a prophage confers new pathogenic properties to a bacterium, such as toxin production, which can lead to increased virulence.

Question 4

Which of the following bacteria is known to acquire toxin genes via phage conversion?

Accepted Answer

Corynebacterium diphtheriae

Question 5

In the generalized animal virus replication pathway, what is the correct order of the six steps?

Accepted Answer

Attachment, Penetration, Uncoating, Replication, Assembly, Release

Question 6

Why are naked animal viruses unable to enter host cells by fusion?

Accepted Answer

They lack an envelope, which is required for membrane fusion with the host cell.

Question 7

Which step in the animal virus replication pathway involves the release of new virions by budding?

Accepted Answer

Release

Question 8

A patient experiences recurring cold sores due to HSV-1. Which type of infection does this represent?

Accepted Answer

Latent infection

Question 9

Which of the following statements about chronic viral infections is correct?

Accepted Answer

They are characterized by continuous release of virions over time and slow progression of disease.

Question 10

Which of the following is a key evolutionary advantage of the lysogenic pathway for temperate phages?

Accepted Answer

It allows the phage genome to persist in the host without killing it, enabling survival during unfavorable conditions.

Question 11

Which step in bacteriophage lytic replication involves packing the genome into the capsid and assembling phage structures?

Accepted Answer

Assembly (maturation)

Question 12

If a viral envelope protein is not embedded in the host cell plasma membrane before budding, what is the likely consequence?

Accepted Answer

The newly formed virion may not be infectious because it lacks necessary envelope proteins for attachment.

Question 13

Which of the following best explains why blocking viral attachment proteins is typically preferred over blocking host cell proteins in antiviral drug design?

Accepted Answer

Blocking viral proteins is more specific and less likely to harm host cells.

Question 14

Which of the following is NOT a step in the generalized animal virus replication pathway?

Accepted Answer

Transduction

Question 15

A bacteriophage infects a bacterial cell and its genome is incorporated into the host genome. What is this integrated viral DNA called?

Accepted Answer

Prophage

Question 16

Which of the following equations best represents the exponential increase in virion number during the replication phase of the lytic cycle, assuming each infected cell produces $$n$$ new virions per cycle and there are $$x$$ infected cells?

Accepted Answer

$$V = n 	imes x$$

Question 17

Which of the following is a real-world consequence of phage conversion in bacteria?

Accepted Answer

Emergence of bacterial strains that produce dangerous toxins, leading to outbreaks of diseases such as diphtheria and botulism.

Question 18

Which of the following statements about persistent viral infections is correct?

Accepted Answer

Persistent infections can be chronic or latent, allowing viruses to evade immune clearance and remain in the host.

Question 19

Which of the following viruses is associated with oncogenesis and can cause cancer in humans?

Accepted Answer

Human papillomavirus (HPV)

CHap 6 B

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