Question 1

Which of the following best describes the 'headful packaging' mechanism in bacteriophage DNA replication?

Accepted Answer

The capsid is filled with DNA until it reaches capacity, then the DNA is cleaved and the process repeats for the next capsid.

Question 2

According to the Baltimore classification, which group of viruses requires reverse transcriptase to replicate its genome?

Accepted Answer

Group VI: Retroviruses (RNA reverse-transcribing viruses)

Question 3

Which property is NOT generally considered a defining characteristic of life, and is debated in the context of viruses?

Accepted Answer

Self-reproduction outside a host cell

Question 4

A virus that infects only humans but not other mammals is said to have which of the following?

Accepted Answer

A narrow host range

Question 5

Which of the following is a key difference between animal viruses and bacteriophages in terms of their replication cycles?

Accepted Answer

Animal viruses face more complex challenges due to the structure of eukaryotic cells.

Question 6

Which of the following is NOT a criterion used by the International Committee on Taxonomy of Viruses (ICTV) for virus classification?

Accepted Answer

Ability to cause disease in humans

Question 7

A viroid differs from a virus in that a viroid:

Accepted Answer

Contains only a short, circular RNA molecule and no protein coat

Question 8

Which of the following best explains why chronic viral infections are more common than acute viral diseases?

Accepted Answer

Chronic infections allow the virus to persist in the host without killing it, increasing transmission opportunities.

Question 9

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that cause disease by inducing abnormal folding of normal proteins.

Question 10

A researcher discovers a new virus with a segmented, double-stranded RNA genome. According to the Baltimore classification, to which group does this virus belong?

Accepted Answer

Group III

Question 11

Which of the following best describes the ecological role of viruses in aquatic environments?

Accepted Answer

Viruses regulate microbial populations and contribute to nutrient cycling.

Question 12

Which of the following is a correct statement about the rolling circle replication mechanism in phage lambda?

Accepted Answer

It produces linear concatemers of DNA that are later cleaved during packaging.

Question 13

Which of the following is a plausible next experiment after annotating figures and drawing conclusions from a virology research paper?

Accepted Answer

Propose a new hypothesis and design an experiment to test it based on the current findings.

Question 14

Which of the following is NOT a possible form that a virus may take during its life cycle?

Accepted Answer

Free-living metabolizing cell

Question 15

Which of the following best explains why antiviral drugs are less common than antibiotics?

Accepted Answer

Viruses use host cell machinery for replication, making it difficult to target the virus without harming the host cell.

Question 16

Which of the following is a key feature of symmetrical virions?

Accepted Answer

They exhibit regular geometric shapes, such as icosahedrons.

Question 17

A virus with a single-stranded, positive-sense RNA genome that serves directly as mRNA for protein synthesis belongs to which Baltimore group?

Accepted Answer

Group IV

Question 18

Which of the following is a correct statement about the host range of viruses?

Accepted Answer

Each species of virus infects a particular group of host species, known as its host range.

Question 19

Which of the following is a plausible reason why viruses are considered to be at the edge of life?

Accepted Answer

They require a host cell for reproduction and lack independent metabolism.

Question 20

Which of the following best describes the relationship between capsid assembly and nucleic acid packaging in phage lambda?

Accepted Answer

Capsid assembly and DNA packaging are tightly linked and occur nearly simultaneously.

Viruses: Structure, Classification, and Life Cycles in Genetics

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