Question 1

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

Accepted Answer

Viruses may contain either DNA or RNA, but never both.

Question 2

A scientist is studying a virus that infects only a specific type of liver cell in humans. What property of the virus is most responsible for this specificity?

Accepted Answer

The affinity of viral surface proteins for host cell receptors

Question 3

Which of the following best explains why viruses are considered acellular?

Accepted Answer

They lack cytoplasmic membrane, cytosol, and organelles.

Question 4

During the lytic replication cycle of a bacteriophage, what is the correct order of the stages?

Accepted Answer

Attachment, Entry, Synthesis, Assembly, Release

Question 5

Which of the following is a unique feature of enveloped viruses compared to non-enveloped (naked) viruses?

Accepted Answer

They acquire a phospholipid bilayer from the host cell during replication or release.

Question 6

A patient is diagnosed with a fatal neurological disease characterized by spongiform degeneration of the brain. Which infectious agent is most likely responsible?

Accepted Answer

A prion

Question 7

Which of the following best describes the process of lysogenic conversion?

Accepted Answer

A phage integrates its genome into the host chromosome, potentially altering the host phenotype.

Question 8

Which of the following is NOT a method used to culture viruses in the laboratory?

Accepted Answer

Growing viruses in nutrient broth without any host cells

Question 9

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that cause normal cellular PrP to misfold into the prion form.

Question 10

A virus is found to have a helical capsid and an envelope. Which of the following is true about its replication and release?

Accepted Answer

It is released from the host cell by budding, which allows persistent infection.

Question 11

Which of the following best explains why some animal viruses can remain dormant in host cells for years?

Accepted Answer

They can exist as proviruses incorporated into the host DNA, remaining latent.

Question 12

Which of the following is a correct statement about viroids?

Accepted Answer

Viroids are extremely small, circular pieces of RNA that infect plants.

Question 13

Which of the following is a real-world example of a virus causing cancer in humans?

Accepted Answer

Kaposi’s sarcoma caused by a herpesvirus

Question 14

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 15

Which of the following is a function of the viral capsid?

Accepted Answer

It provides protection for viral nucleic acid and aids in attachment to host cells.

Question 16

A virus is classified as a generalist. What does this mean?

Accepted Answer

It infects many kinds of cells in many different hosts.

Question 17

Which of the following best describes the difference in replication location between DNA and RNA animal viruses?

Accepted Answer

DNA viruses often replicate in the nucleus, while RNA viruses often replicate in the cytoplasm.

Question 18

Which of the following is the most effective method for destroying prions?

Accepted Answer

Autoclaving in 1 M NaOH solution

Question 19

Which of the following is a plausible consequence of lysogenic conversion in bacteria?

Accepted Answer

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

Question 20

Which of the following best explains why viruses are not considered alive by some scientists?

Accepted Answer

They cannot reproduce independently and lack cellular structure.

Characterizing and Classifying Viruses, Viroids, and Prions

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