Question

What is the primary role of reverse transcriptase in recombinant DNA technology?

• A. To synthesize DNA from an RNA template
• B. To cut DNA at specific sites
• C. To join DNA fragments
• D. To amplify DNA sequences

Hint:

Reverse transcriptase = \textbf{RNA $\rightarrow$ DNA}. Opposite of normal transcription.

Answer 1

The Correct Option is A

Concept: Reverse transcriptase is an enzyme that synthesizes complementary DNA (cDNA) from an RNA template. It is naturally found in retroviruses and is widely used in molecular biology and recombinant DNA technology.

• It converts mRNA into cDNA.
• cDNA lacks introns, making it useful for cloning eukaryotic genes.

Step 1: Understand the function of reverse transcriptase.
Unlike normal transcription (DNA $\rightarrow$ RNA), reverse transcriptase works in the opposite direction (RNA $\rightarrow$ DNA).
Step 2: Identify its role in biotechnology.
It is used to generate cDNA libraries and clone genes from mRNA, especially when working with eukaryotic genes that contain introns.
Step 3: Differentiate from other enzymes.

• Restriction enzymes cut DNA.
• DNA ligase joins DNA fragments.
• DNA polymerase amplifies DNA (PCR).

Step 4: Conclude the answer.
Thus, the primary role of reverse transcriptase is to synthesize DNA from an RNA template.