Question 1

Which of the following best describes the function of a viral capsid?

Accepted Answer

It is the protein coat that surrounds and protects the viral genome.

Question 2

A bacteriophage infects a bacterial cell and integrates its DNA into the host genome. What is the term for the integrated viral DNA?

Accepted Answer

Prophage

Question 3

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that can cause brain diseases by inducing misfolding of normal proteins.

Question 4

During the lytic cycle of a bacteriophage, which event occurs first after the virus attaches to the host cell?

Accepted Answer

The viral genome is injected into the host cell.

Question 5

Which enzyme is responsible for converting viral RNA into DNA in retroviruses?

Accepted Answer

Reverse transcriptase

Question 6

A double-stranded DNA virus infects a human cell. Where does its genome typically replicate?

Accepted Answer

In the nucleus during S phase of the cell cycle

Question 7

Which of the following best explains why viroids are unique among infectious agents?

Accepted Answer

They consist solely of short, circular, single-stranded RNA and do not encode proteins.

Question 8

A positive-sense RNA virus enters a host cell. What is the first step in its replication?

Accepted Answer

Its genome is immediately translated into viral proteins.

Question 9

Which of the following is a key difference between the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

The lytic cycle results in host cell death, while the lysogenic cycle allows the host cell to survive with integrated viral DNA.

Question 10

Which structure on animal viruses is derived from the host cell membrane and aids in cell entry?

Accepted Answer

Viral envelope

Question 11

A negative-sense RNA virus must carry which enzyme to ensure successful replication in the host cell?

Accepted Answer

Viral RNA polymerase

Question 12

Which of the following best describes the role of host cell surface proteins in viral infection?

Accepted Answer

They act as receptors that viruses recognize and bind to for cell entry.

Question 13

Which of the following is true about temperate phages?

Accepted Answer

They are capable of replicating through both the lytic and lysogenic cycles.

Question 14

What is the main reason why many bacteria have restriction enzymes?

Accepted Answer

To degrade viral DNA and defend against phage infection.

Question 15

Which of the following best explains why retroviruses are difficult to eradicate from a host organism?

Accepted Answer

Their RNA genome is reverse transcribed and integrated into the host's DNA, allowing persistent infection.

Question 16

A scientist observes a pathogen that disrupts plant growth but does not encode any proteins. What is the most likely identity of this pathogen?

Accepted Answer

Viroid

Question 17

Which of the following equations correctly represents the process catalyzed by reverse transcriptase in retroviruses?

Accepted Answer

$$RNA \rightarrow DNA$$

Question 18

A virus with a single-stranded RNA genome that is complementary to the viral mRNA is classified as:

Accepted Answer

Negative-sense RNA virus

Question 19

Which of the following best describes the process of endocytosis in viral infection?

Accepted Answer

The host cell engulfs the virus, allowing the viral genome to enter the cell.

Question 20

Which of the following is a plausible consequence of prion accumulation in animal brains?

Accepted Answer

Neurodegenerative diseases due to misfolded protein aggregates.

Viruses and Other Infectious Agents: Structure, Replication, and Diversity

Study Guide - Practice Questions