Q: Which of the following equations best represents the process catalyzed by reverse transcriptase in retroviruses?

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

Question 1

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

Accepted Answer

They require host cell machinery to replicate and assemble new virions.

Question 2

A scientist discovers a new virus with a single-stranded RNA genome that acts directly as mRNA upon infection. Which of the following best describes the replication strategy of this virus?

Accepted Answer

The host ribosomes immediately translate the viral RNA to produce proteins.

Question 3

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

Accepted Answer

They are composed solely of protein and lack nucleic acids.

Question 4

A patient is diagnosed with cervical cancer caused by human papillomavirus (HPV). Which viral property is most directly responsible for the development of cancer in this case?

Accepted Answer

The virus encodes an oncogene that disrupts cell cycle regulation.

Question 5

Which of the following best describes the function of reverse transcriptase in retroviruses?

Accepted Answer

It synthesizes a complementary DNA strand from an RNA template.

Question 6

Viroids differ from viruses in that viroids:

Accepted Answer

Consist of small, circular RNA molecules without a protein coat.

Question 7

During the viral life cycle, which step involves the spontaneous assembly of capsid proteins and nucleic acid to form a mature virion?

Accepted Answer

Assembly

Question 8

A plant is genetically engineered to express the coat protein of a virus. What is the most likely outcome of this modification?

Accepted Answer

The plant may become susceptible to infection if the virus can use the expressed coat protein for its own assembly.

Question 9

Which of the following best explains why prion diseases are difficult to control in livestock populations?

Accepted Answer

Prions can be transmitted through consumption of infected animal tissue and are highly resistant to degradation.

Question 10

Which of the following equations best represents the process catalyzed by reverse transcriptase in retroviruses?

Accepted Answer

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

Question 11

A virus with a double-stranded DNA genome infects a host cell. Which of the following steps must occur for the virus to produce its capsid proteins?

Accepted Answer

Viral DNA is transcribed into mRNA, which is then translated by host ribosomes.

Question 12

Which of the following best describes the role of the viral envelope in infection?

Accepted Answer

It contains host-derived phospholipids and viral glycoproteins that facilitate entry into host cells.

Question 13

A researcher is studying a virus that requires the host cell to be in S phase for successful replication. Which of the following best explains this requirement?

Accepted Answer

The virus depends on host DNA polymerase, which is most active during S phase.

Question 14

Which of the following is a correct statement about the synthesis of viral proteins in HIV infection?

Accepted Answer

All HIV proteins are translated as a single polyprotein, which is then cleaved by a viral protease.

Question 15

Which of the following best explains why viroids can cause disease in plants despite lacking protein-coding genes?

Accepted Answer

Viroids interfere with host gene expression by base pairing with plant mRNAs.

Question 16

A virus is found to have a segmented RNA genome. Which of the following is a potential consequence of this genome structure?

Accepted Answer

The virus can undergo reassortment, leading to rapid genetic variation.

Question 17

Which of the following best describes the process of viral release by budding?

Accepted Answer

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

Question 18

Which of the following is a plausible reason why the introduction of protease inhibitors dramatically improved HIV therapy?

Accepted Answer

Protease inhibitors prevent the cleavage of the HIV polyprotein, blocking the formation of functional viral proteins.

Question 19

Which of the following best explains why viruses are not classified as living organisms?

Accepted Answer

They lack a cell membrane and cannot carry out independent metabolism.

Viruses: Structure, Physiology, Life Cycle, and Related Infectious Agents

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