Which option correctly describes reverse transcriptase activity in RT-PCR workflows?

Which option correctly describes reverse transcriptase activity in RT-PCR workflows?

• A. To degrade RNA templates during PCR.
• B. To synthesize DNA from a DNA template.
• C. To synthesize complementary DNA from RNA.
• D. To ligate DNA fragments.

Answer: (C)

In RT-PCR workflows, the key role of reverse transcriptase is to synthesize complementary DNA from RNA. Reverse transcriptase is an RNA-dependent DNA polymerase, meaning it reads an RNA template and builds a DNA strand complementary to that RNA, producing cDNA. This is crucial because PCR amplifies DNA, not RNA, so converting the RNA target (such as a viral genome or an mRNA transcript) into cDNA lets the subsequent PCR steps amplify and detect it. After the cDNA is created, a standard DNA polymerase carries out PCR amplification through cycles of denaturation, annealing, and extension. The other described activities—degrading RNA templates, synthesizing DNA from a DNA template, or ligating DNA fragments—aren’t what reverse transcriptase does in this workflow. The essential concept is turning RNA into DNA so it can be amplified and measured.

In RT-PCR workflows, the key role of reverse transcriptase is to synthesize complementary DNA from RNA. Reverse transcriptase is an RNA-dependent DNA polymerase, meaning it reads an RNA template and builds a DNA strand complementary to that RNA, producing cDNA. This is crucial because PCR amplifies DNA, not RNA, so converting the RNA target (such as a viral genome or an mRNA transcript) into cDNA lets the subsequent PCR steps amplify and detect it. After the cDNA is created, a standard DNA polymerase carries out PCR amplification through cycles of denaturation, annealing, and extension. The other described activities—degrading RNA templates, synthesizing DNA from a DNA template, or ligating DNA fragments—aren’t what reverse transcriptase does in this workflow. The essential concept is turning RNA into DNA so it can be amplified and measured.