Question 1

Which of the following statements best describes why viruses are considered obligate intracellular parasites?

Accepted Answer

They require living host cells to multiply because they lack metabolic machinery.

Question 2

A virus is found to have a genome composed of double-stranded DNA and is nonenveloped. Which family is it most likely to belong to?

Accepted Answer

Adenoviridae

Question 3

Which step in the lytic cycle of a T-even bacteriophage involves the production of phage DNA and proteins?

Accepted Answer

Biosynthesis

Question 4

A researcher observes viral plaques on a bacterial lawn. What does each plaque represent?

Accepted Answer

A single virus particle that has lysed multiple bacterial cells

Question 5

Which of the following is TRUE regarding the viral genome?

Accepted Answer

It may be single-stranded or double-stranded, and linear or circular.

Question 6

Which of the following best explains why animal viruses are often grown in embryonated eggs for vaccine production?

Accepted Answer

Eggs allow for easy detection of viral growth by changes or death of the embryo.

Question 7

Which of the following is a correct description of the Baltimore classification system for viruses?

Accepted Answer

It groups viruses according to their nucleic acid type and how mRNA is produced.

Question 8

A virus with a helical capsid and an envelope is most likely to enter a host cell by which mechanism?

Accepted Answer

Receptor-mediated endocytosis or fusion with the plasma membrane

Question 9

Which of the following viruses uses reverse transcriptase to produce DNA from its RNA genome?

Accepted Answer

Hepatitis B virus

Question 10

During the lysogenic cycle of bacteriophage lambda ($$\lambda$$), which of the following events occurs?

Accepted Answer

Phage DNA is incorporated into the host cell DNA as a prophage.

Question 11

Which of the following is a potential outcome of lysogeny in bacteria infected by a temperate phage?

Accepted Answer

Immunity to reinfection by the same phage

Question 12

Which of the following best describes the role of spikes on the surface of some viruses?

Accepted Answer

They facilitate attachment to host cell receptors.

Question 13

A patient is diagnosed with a persistent viral infection. Which of the following best characterizes this type of infection?

Accepted Answer

The infection occurs gradually over a long period and is generally fatal.

Question 14

Which of the following viruses is known to cause transformation of normal cells into tumor cells?

Accepted Answer

Human papillomavirus (HPV)

Question 15

Which laboratory method is commonly used to identify viruses by their reaction with antibodies?

Accepted Answer

ELISA

Question 16

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that can cause neurodegenerative diseases.

Question 17

Which of the following best explains why plant viruses often require wounds or insect vectors to infect plant cells?

Accepted Answer

Plant cells are generally protected from disease by an impermeable cell wall.

Question 18

Which of the following is a distinguishing feature of viroids compared to viruses?

Accepted Answer

Viroids consist solely of short pieces of naked RNA.

Question 19

A virus is found to have a single-stranded RNA genome and is enveloped. Which of the following viruses fits this description and is known to cause respiratory infections?

Accepted Answer

Coronavirus

Question 20

Which of the following steps is unique to the multiplication of enveloped animal viruses compared to nonenveloped viruses?

Accepted Answer

Release by budding from the host cell membrane

Viruses, Viroids, and Prions: Structure, Classification, and Pathogenesis

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