Question 1

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

Accepted Answer

It is the protein coat that covers the viral genome and may have many different forms.

Question 2

A bacteriophage injects its DNA into a bacterial cell. Which viral replication cycle will result in immediate destruction of the host cell?

Accepted Answer

Lytic cycle

Question 3

Which of the following is TRUE about retroviruses?

Accepted Answer

They use reverse transcriptase to convert their RNA genome into DNA.

Question 4

What is the main difference between the lytic and lysogenic cycles in bacteriophage replication?

Accepted Answer

The lytic cycle results in host cell death, while the lysogenic cycle integrates viral DNA into the host genome.

Question 5

Which of the following best describes a viroid?

Accepted Answer

A small, circular, single-stranded RNA pathogen that infects plants.

Question 6

A virus with a positive-sense RNA genome can immediately:

Accepted Answer

Be translated by host ribosomes to produce viral proteins.

Question 7

Which of the following is a key feature of prions?

Accepted Answer

They are infectious proteins that can cause brain diseases in animals.

Question 8

Which step is common to both animal virus and bacteriophage replication?

Accepted Answer

Hijacking the host's replicative machinery to produce viral components.

Question 9

Which of the following statements about viral envelopes is correct?

Accepted Answer

They are accessory structures found in animal viruses and derived from the host cell membrane.

Question 10

A scientist discovers a new infectious agent that lacks nucleic acids but causes neurodegenerative disease in mammals. What is the most likely identity of this agent?

Accepted Answer

Prion

Question 11

Which enzyme is used by retroviruses to synthesize DNA from their RNA genome?

Accepted Answer

Reverse transcriptase

Question 12

Which of the following best explains why antibiotics are ineffective against viruses?

Accepted Answer

Viruses lack the cellular structures targeted by antibiotics, such as cell walls and ribosomes.

Question 13

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

Accepted Answer

Attachment, injection of DNA, synthesis of viral components, assembly, lysis

Question 14

A virus that integrates its DNA into the host genome and remains dormant for several generations is undergoing which cycle?

Accepted Answer

Lysogenic cycle

Question 15

Which of the following best describes the genome of a viroid?

Accepted Answer

Single-stranded, circular RNA

Question 16

Which of the following is a real-world example of a disease caused by prions?

Accepted Answer

Mad cow disease (Bovine spongiform encephalopathy)

Question 17

Which of the following steps is unique to retroviral replication compared to other animal viruses?

Accepted Answer

Reverse transcription of RNA into DNA

Question 18

Which of the following best describes the role of the viral envelope in animal viruses?

Accepted Answer

It helps the virus enter host cells by fusing with the host membrane.

Question 19

Which of the following statements about positive-sense RNA viruses is correct?

Accepted Answer

Their genome can be directly translated by host ribosomes.

Question 20

Which of the following is NOT a characteristic of viruses?

Accepted Answer

They can replicate independently outside of host cells.

Viruses: Structure, Replication, and Other Infectious Agents

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