Question

1. The virus repressor protein
A) controls the prophage's lytic genes but not the incoming genomes of the same virus.
B) does not control the prophage's lytic genes but does control the incoming genomes of the same virus.
C) controls both the lytic genes on the prophage and prevents an incoming virus of the same type.
D) has different actions in different situations.

2. The primer for retrovirus reverse transcription is a specific
A) tRNA encoded by the cell.
B) tRNA encoded by the virus.
C) nuclear tRNA.
D) nuclear tDNA.

Please provide a detailed explanation along with the answers.

Answer 1

Answer for question 1: A

Explanation:

• phage are classified into two lytic and lysogenic based on their mechanisms
• Lytic cycle results the infection of virulent gene into the host and kill the host cell.
• Lysogenic cycle results in the phage genome to integrate into host genome after entering into the host cell. In this cycle, phage genome or prophage replicate along with the host genome and also phage genome never express alone.
• So that the viral repressor mainly helps to maintain the lysogenic state. It mainly to control the lytic genome and prevent the incoming phage genome ( this may helps to impart the infection caused by the same virus).

Answer for question 2: A

Explanation:

• Host cell tRNA serve as primer for retrovirus during reverse transcription. Because 3’ end of tRNA is complementary to primer binding site of the retrovirus genome. This is the reason why tRNA helps to initiate the reverse transcription of retrovirus.

Thank you. All the best?