$$RNA \xrightarrow{\text{reverse transcriptase}} DNA$$

$$+RNA \xrightarrow{\text{RNA-dependent RNA polymerase}} -RNA \xrightarrow{\text{RNA-dependent RNA polymerase}} +RNA$$

Question 1

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

Accepted Answer

They require a host cell to replicate because they lack ribosomes and an ATP-generating mechanism.

Question 2

A scientist is studying a virus that has a helical capsid, an envelope, and spikes. Which of the following viruses is most likely being studied?

Accepted Answer

Influenzavirus

Question 3

Which of the following best explains the host range of a virus?

Accepted Answer

It is determined by specific host attachment sites and cellular factors.

Question 4

A bacteriophage is observed to integrate its DNA into the host genome and remain dormant for several generations. This process is known as:

Accepted Answer

The lysogenic cycle

Question 5

Which of the following equations best represents the process of reverse transcription in retroviruses?

Accepted Answer

$$RNA \xrightarrow{	ext{reverse transcriptase}} DNA$$

Question 6

Which of the following is a unique feature of prions compared to viruses?

Accepted Answer

They are composed solely of protein with no nucleic acid.

Question 7

A patient presents with cold sores that recur during periods of stress. Which viral property best explains this phenomenon?

Accepted Answer

Latent infection

Question 8

Which of the following best describes the process of specialized transduction?

Accepted Answer

Only bacterial genes adjacent to the prophage are transferred by a lysogenic phage.

Question 9

Which of the following virus families is associated with the formation of tumors in humans?

Accepted Answer

Papovaviridae

Question 10

A researcher is growing animal viruses in the laboratory. Which of the following methods would NOT be suitable for culturing these viruses?

Accepted Answer

Using a lawn of bacteria on agar plates

Question 11

Which of the following best describes the function of viral spikes?

Accepted Answer

They are used for attachment to host cells and viral identification.

Question 12

Which of the following is a correct pairing of virus family and associated disease?

Accepted Answer

Orthomyxoviridae – Influenza

Question 13

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

Accepted Answer

Uncoating of the viral genome by host or viral enzymes

Question 14

A virus is classified as a double-stranded DNA, enveloped virus. Which of the following families could it belong to?

Accepted Answer

Herpesviridae

Question 15

Which of the following best explains why viruses are generally much smaller than bacteria?

Accepted Answer

Viruses lack cellular structures such as ribosomes and organelles.

Question 16

Which of the following equations represents the replication of a (+) sense RNA virus?

Accepted Answer

$$+RNA \xrightarrow{	ext{RNA-dependent RNA polymerase}} -RNA \xrightarrow{	ext{RNA-dependent RNA polymerase}} +RNA$$

Question 17

Which of the following is a characteristic of viroids?

Accepted Answer

They are short pieces of infectious RNA without a protein coat.

Question 18

A patient is diagnosed with subacute sclerosing panencephalitis, a persistent viral infection. Which virus is most likely responsible?

Accepted Answer

Measles virus

Question 19

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

Accepted Answer

The virus acquires its envelope from the host cell plasma membrane as it exits.

Question 20

Which of the following laboratory techniques can be used to identify viruses by detecting antibodies in a patient’s serum?

Accepted Answer

Serological tests

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

Study Guide - Practice Questions