Question 1

Which of the following statements best describes the genetic material of viruses?

Accepted Answer

Viruses may have DNA or RNA, which can be single- or double-stranded, but never both.

Question 2

Which of the following is NOT a characteristic of viruses?

Accepted Answer

They can reproduce independently outside a host cell.

Question 3

A virus that infects only a specific type of cell within a specific host demonstrates which property?

Accepted Answer

Host specificity due to affinity between viral and host proteins

Question 4

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

Accepted Answer

It is composed of protein subunits called capsomeres and provides protection and attachment to host cells.

Question 5

Which of the following is a correct sequence of events in the lytic replication cycle of a bacteriophage?

Accepted Answer

Attachment → Entry → Synthesis → Assembly → Release

Question 6

During lysogenic replication, what is the term for the inactive phage DNA integrated into the host chromosome?

Accepted Answer

Prophage

Question 7

Which of the following mechanisms is NOT a method by which animal viruses enter host cells?

Accepted Answer

Binary fission

Question 8

Which of the following statements about viral envelopes is TRUE?

Accepted Answer

Viral envelopes are acquired from the host cell membrane during replication or release.

Question 9

A retrovirus differs from other RNA viruses in that it:

Accepted Answer

Uses a DNA intermediary transcribed by reverse transcriptase to replicate.

Question 10

Which of the following best explains why enveloped viruses are generally more fragile than naked viruses?

Accepted Answer

Their envelopes are easily disrupted by environmental factors, leading to loss of infectivity.

Question 11

Which of the following is a possible outcome of lysogenic conversion?

Accepted Answer

The host cell acquires new traits, such as toxin production, due to phage genes.

Question 12

Which of the following is NOT a criterion used to classify viruses?

Accepted Answer

Ability to metabolize glucose

Question 13

Which of the following best describes the process of budding in enveloped viruses?

Accepted Answer

The virus acquires its envelope from the host cell membrane as it exits the cell.

Question 14

Which of the following is a real-world example of a cancer caused by a virus?

Accepted Answer

Kaposi’s sarcoma

Question 15

Which of the following equations best represents the burst size in a lytic viral replication cycle?

Accepted Answer

$$	ext{Burst size} = \frac{	ext{Number of virions released}}{	ext{Number of infected cells}}$$

Question 16

A patient is diagnosed with a viral infection. The virus is found to remain dormant in the host cell for years without causing symptoms. What is this phenomenon called?

Accepted Answer

Latency

Question 17

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

Accepted Answer

They cannot carry out metabolic processes independently.

Question 18

Which of the following is a function of viral glycoproteins (spikes) found on enveloped viruses?

Accepted Answer

They mediate attachment to host cell receptors.

Question 19

Which of the following best describes the difference in site of synthesis between DNA and RNA animal viruses?

Accepted Answer

DNA viruses typically synthesize in the nucleus, while RNA viruses synthesize in the cytoplasm.

Question 20

Which of the following is a possible consequence of viral interference with tumor repression in host cells?

Accepted Answer

Uncontrolled cell division leading to cancer

Characterizing and Classifying Viruses, Viroids, and Prions: Study Notes

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