Question 1

Which of the following is a characteristic that distinguishes viruses from typical bacteria?

Accepted Answer

Viruses lack an ATP-generating mechanism.

Question 2

A virus infects only CD4$$^+$$ cells in humans. What determines this host specificity?

Accepted Answer

Specific attachment sites on the host cell and cellular factors.

Question 3

Which of the following statements about bacteriophages is correct?

Accepted Answer

Bacteriophages are viruses that infect bacteria.

Question 4

Why are viruses considered obligate intracellular parasites?

Accepted Answer

They require living host cells to multiply.

Question 5

Which of the following is NOT found in a typical virus?

Accepted Answer

Ribosomes

Question 6

A virus is 50 nm in diameter. Can it be visualized using a light microscope with a resolution limit of 200 nm?

Accepted Answer

No, because it is smaller than the resolution limit.

Question 7

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

Accepted Answer

Viruses may contain either DNA or RNA, but not both.

Question 8

Which of the following is a correct comparison between viruses and typical bacteria?

Accepted Answer

Viruses are sensitive to interferon, while typical bacteria are not.

Question 9

What is the primary reason viruses cannot be treated with antibiotics?

Accepted Answer

Viruses lack a cell wall targeted by antibiotics.

Question 10

Which of the following statements about the host range of viruses is correct?

Accepted Answer

The host range is determined by specific attachment sites and cellular factors.

Question 11

A scientist observes clearings on a bacterial lawn after adding a virus sample. What are these clearings called, and what do they represent?

Accepted Answer

Plaques; each represents a single virus.

Question 12

Which of the following is true regarding the size of viruses?

Accepted Answer

Viruses range from 20 nm to 1000 nm in length.

Question 13

Which of the following is a correct statement about the replication of viruses?

Accepted Answer

Viruses require host cell machinery to replicate.

Question 14

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

Accepted Answer

Gram staining

Question 15

Which of the following is a correct statement about the structure of viruses?

Accepted Answer

All viruses have a protein coat called a capsid.

Question 16

Which of the following is a correct statement about the replication of bacteriophages?

Accepted Answer

Bacteriophages form plaques on bacterial lawns.

Question 17

Which of the following is NOT a characteristic of viruses?

Accepted Answer

Contains ribosomes

Question 18

Which of the following statements about the cultivation of animal viruses is correct?

Accepted Answer

Animal viruses can be cultured in living animals, embryonated eggs, or cell cultures.

Question 19

Which of the following is true about the sensitivity of viruses to interferon?

Accepted Answer

Viruses are sensitive to interferon.

Question 20

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

Accepted Answer

Bacteriophages infect only bacteria.

Viruses, Viroids, and Prions: Structure, Classification, and Comparison with Bacteria

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