Question

Once tRNA has annealed to the plus-strand RNA (the viral RNA that will be turned into DNA), reverse transcriptase starts synthesis of the (minus/plus) strand DNA?

1) minus
2) plus

Answer 1

Reverse transcriptase synthesizes the minus-strand DNA from the annealed tRNA and the plus-strand RNA in retroviruses like HIV. This minus-strand DNA then serves as a template for creating the complementary plus-strand DNA.

Step-by-step explanation:

Once tRNA has annealed to the plus-strand RNA (the viral RNA that will be turned into DNA), reverse transcriptase starts synthesis of the minus strand DNA. The correct answer is 1) minus. In the process of reverse transcription found in retroviruses such as HIV, the enzyme reverse transcriptase utilizes the +ssRNA viral genome as a template to synthesize a complementary single-strand DNA (cDNA).

This cDNA is the minus-strand DNA because it is complementary to the plus-strand RNA. After the minus-strand cDNA is synthesized, it serves as a template to form the plus-strand DNA, resulting in a double-stranded DNA (dsDNA). This dsDNA can then integrate into the host's genome to form a provirus, which is capable of directing the synthesis of viral RNA and proteins for new virions.