Q: A patient is diagnosed with chronic hepatitis and jaundice. Laboratory tests reveal infection with a DNA virus that uses reverse transcription during replication. Which of the following sequences correctly represents the genome replication steps of this virus?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{DNA}$$

Question 1

Which of the following best describes the role of reverse transcriptase in the life cycle of Hepatitis B virus (HBV)?

Accepted Answer

It synthesizes DNA from an RNA template after the viral genome is transcribed.

Question 2

A patient is diagnosed with chronic hepatitis and jaundice. Laboratory tests reveal infection with a DNA virus that uses reverse transcription during replication. Which of the following sequences correctly represents the genome replication steps of this virus?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{DNA}$$

Question 3

Which of the following statements about overlapping open reading frames (ORFs) in the HBV genome is correct?

Accepted Answer

Overlapping ORFs allow HBV to produce multiple proteins from a small genome.

Question 4

Which gene in the HBV genome encodes the viral reverse transcriptase activity?

Accepted Answer

P gene

Question 5

A researcher is studying a virus with the following properties: +RNA genome, uses reverse transcriptase, integrates into the host chromosome, and produces polyproteins that are later cleaved. Which virus is being described?

Accepted Answer

Human Immunodeficiency Virus (HIV)

Question 6

During HIV replication, which enzyme is responsible for inserting the viral DNA into the host chromosome?

Accepted Answer

Integrase

Question 7

What is the function of HIV protease during the viral life cycle?

Accepted Answer

It cleaves viral polyproteins into functional proteins.

Question 8

SV40 Large T-antigen is known to contribute to cellular transformation by inhibiting which cellular protein?

Accepted Answer

p53

Question 9

A scientist is using a virus as a vector to deliver a therapeutic gene into human cells. The virus is non-enveloped, has a double-stranded DNA genome, and is known to cause respiratory infections. Which virus is most likely being used?

Accepted Answer

Adenovirus

Question 10

Which of the following best explains why certain types of human papillomavirus (HPV) are associated with cancer development?

Accepted Answer

They produce viral proteins that interfere with cellular tumor-suppressor pathways.

Question 11

Which herpesvirus is responsible for causing chickenpox and shingles?

Accepted Answer

Varicella-zoster virus (VZV)

Question 12

A key feature of herpesviruses is their ability to establish latency. What does viral latency mean?

Accepted Answer

The viral genome remains in the host cell without continuous production of new virus.

Question 13

Which of the following statements about Mimivirus is correct?

Accepted Answer

It has a very large DNA genome but does not have its own ribosomes.

Question 14

Which of the following viruses is correctly matched with its key feature?

Accepted Answer

SV40: Large T-antigen inhibits p53

Question 15

A patient presents with infectious mononucleosis. Which virus is most likely responsible for this condition?

Accepted Answer

Epstein-Barr virus (EBV)

Question 16

Which of the following best distinguishes DNA polymerase from reverse transcriptase?

Accepted Answer

DNA polymerase synthesizes DNA from a DNA template, while reverse transcriptase synthesizes DNA from an RNA template.

Question 17

Which of the following viruses is non-enveloped, has a small double-stranded DNA genome, and is associated with the development of cervical cancer?

Accepted Answer

Human papillomavirus (HPV)

Question 18

A virus is found to infect amoebas, is about $$0.5\ \mu m in $$size, and contains around 900 protein-coding genes. Which of the following is true about this virus?

Accepted Answer

It depends on the host cell for essential cellular functions.

Question 19

Which of the following is NOT a function of the HIV reverse transcriptase enzyme?

Accepted Answer

Integrating viral DNA into the host chromosome

Question 20

Which of the following best explains why HBV is considered unusual among DNA viruses?

Accepted Answer

It uses reverse transcription during its replication cycle.

DNA Viruses and Reverse Transcriptase: Animal and Plant Viruses

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