Reverse transcriptase is an enzyme unique to the retroviruses. Which one of the following is a function of the enzyme reverse transcriptase?: (A) DNase activity, (B) RNA-dependent RNA polymerase activity, (C) RNA isomerase activity, (D) RNA-dependent DNA polymerase activity
Answer is D. The replication of a retroviral genome is dependent on the reverse transcriptase enzyme, which performs a variety of functions. It builds a complementary strand of DNA for the viral RNA template; it builds a second DNA strand complementary to the previous DNA; it degrades the original RNA, leaving a DNA-DNA duplex; and, finally, it is responsible for integrating the new viral DNA hybrid into the host genome.