Question 1

Which of the following statements best describes why viruses are considered acellular?

Accepted Answer

They lack a cytoplasmic membrane, cytosol, and organelles.

Question 2

A scientist discovers a new infectious agent that contains a protein coat and a nucleic acid, but no phospholipid envelope. What is the most accurate term for this agent in its extracellular state?

Accepted Answer

Virion

Question 3

Which feature is used as a primary method for classifying viruses?

Accepted Answer

Type of nucleic acid present

Question 4

A virus with a genome consisting of segmented, double-stranded RNA would be classified as which type?

Accepted Answer

dsRNA virus

Question 5

Why are enveloped viruses generally more fragile than naked viruses?

Accepted Answer

Their phospholipid bilayer envelope is easily disrupted by environmental factors.

Question 6

Which of the following best explains the host specificity of most viruses?

Accepted Answer

Affinity of viral surface proteins for complementary proteins on host cell surfaces.

Question 7

During the lytic replication cycle, which stage immediately follows attachment?

Accepted Answer

Entry

Question 8

A bacteriophage infects a bacterial cell and its genome integrates into the host DNA, remaining inactive for several generations. What is this inactive viral DNA called?

Accepted Answer

Prophage

Question 9

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

Accepted Answer

Tail fiber injection

Question 10

Retroviruses differ from other RNA viruses in their replication strategy. Which enzyme is crucial for retrovirus replication?

Accepted Answer

Reverse transcriptase

Question 11

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

Accepted Answer

The virus acquires a portion of the host cell membrane as it exits.

Question 12

What is the consequence of viral latency in animal cells?

Accepted Answer

The virus remains dormant and may be reactivated years later.

Question 13

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

Accepted Answer

Kaposi's sarcoma

Question 14

A virus is found to have a helical capsid. Which of the following is true about its structure?

Accepted Answer

Its capsomeres are arranged in a spiral around the nucleic acid.

Question 15

Which of the following equations best represents the burst size in the lytic cycle, where $$N_{final} is $$the number of virions released and $$N_{initial} is $$the number of infected cells?

Accepted Answer

$$Burst\ Size = \frac{N_{final}}{N_{initial}}$$

Question 16

Which of the following is NOT a way that viruses can contribute to the development of cancer?

Accepted Answer

Directly repairing damaged DNA in host cells

Question 17

Which of the following statements about viral genomes is correct?

Accepted Answer

Viral genomes are much smaller than those of cells.

Question 18

A virus infects a cell and uses the host's metabolic pathways to replicate. What does this indicate about the virus?

Accepted Answer

It is dependent on the host cell for reproduction.

Question 19

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

Accepted Answer

They cannot reproduce independently or carry out metabolic pathways.

Question 20

Which of the following is a plausible reason why a virus might only infect a specific type of cell within a particular host?

Accepted Answer

The virus's surface proteins specifically bind to complementary receptors on the target cell.

Characterization and Classification of Viruses, Viroids, and Prions

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