In transcription, what enzyme synthesizes RNA from a DNA template?

• A. Helicase.
• B. RNA polymerase.
• C. DNA polymerase.
• D. Ligase.

Answer: (B)

Transcription uses RNA polymerase to build an RNA molecule from the DNA template. This enzyme reads the DNA sequence and links ribonucleotides together in the 5′ to 3′ direction to form the RNA strand, without needing a primer. Helicase simply unwinds the DNA to create the transcription bubble, but it does not synthesize RNA. DNA polymerase makes DNA during replication and requires a primer. Ligase seals nicks in the backbone after synthesis. So, RNA polymerase is the enzyme responsible for RNA synthesis from a DNA template during transcription.