Question

Reverse transcriptase are those which

• A. Disintegrates host DNA
• B. Polymerises host DNA
• C. Translates host DNA
• D. Transcribes viral RNA to cDNA

Answer 1

Answer: (D)

Transcribes viral RNA to cDNA

Restriction endonucleases recognize specific sequences in the DNA and cut the DNA into fragments. The specific sites are 4-6 bp long and are called as restriction sites. Option A is incorrect. The DNA synthesized using RNA template is known as cDNA or complementary DNA. RNA retroviruses have reverse transcriptase enzyme that synthesizes a DNA copy (cDNA) of viral RNA. Option D is correct. The cDNA is made into double stranded molecule which is integrated into host genome. The host DNA is replicated using host cell machinery, DNA polymerase using the parental DNA template, not by reverse transcriptase. Option B is incorrect. The DNA is first transcribed by host cell RNA polymerase and then translated using host cell machinery. Option C is incorrect. Option D is correct.