Final answer:
Reverse transcriptase synthesizes DNA from an RNA template, enabling the replication of retroviruses like HIV by incorporating the DNA into the host genome. This process violates the central dogma of molecular biology by producing DNA from RNA, and reverse transcriptase is also used as a laboratory tool for creating cDNA through RT-PCR.
Step-by-step explanation:
The function of reverse transcriptase is to synthesize a strand of DNA that is complementary to its RNA template. This enzyme is crucial for the replication of retroviruses, such as HIV, which have an RNA genome. The reverse transcriptase enzyme allows the RNA genome to be reverse transcribed into DNA, which can then integrate into the host cell's genome. This newly formed viral DNA is subsequently used to produce new viral RNA genomes and the mRNAs needed to make viral proteins, ultimately resulting in the assembly of new virions.
Contrary to normal transcription, where DNA serves as a template to create RNA, reverse transcriptase carries out the opposite process. This step is a notable exception to the central dogma of molecular biology, which usually involves DNA being transcribed into RNA, and RNA being translated into proteins, without RNA serving as a template for DNA synthesis.
In the laboratory, reverse transcriptase is also employed as a tool for the creation of complementary DNA (cDNA) from an RNA sequence during processes like reverse transcriptase PCR (RT-PCR).