What is the primary function of RNA polymerase during transcription?

• A. It translates mRNA into proteins.
• B. It synthesizes RNA from a DNA template.
• C. It adds amino acids to a growing polypeptide chain.
• D. It unwinds the double-stranded DNA for replication.

Answer: (B)

Verified step by step guidance

1. Understand the process of transcription: Transcription is the process by which genetic information in DNA is copied into RNA. This is a crucial step in gene expression.
2. Identify the role of RNA polymerase: RNA polymerase is the enzyme responsible for synthesizing RNA during transcription. It uses a DNA template to create a complementary RNA strand.
3. Clarify the mechanism: RNA polymerase binds to the promoter region of the DNA, unwinds the double-stranded DNA locally, and begins synthesizing RNA by matching RNA nucleotides to the complementary DNA bases.
4. Distinguish transcription from translation: Transcription involves the synthesis of RNA, while translation is the process where mRNA is used to assemble proteins. RNA polymerase is not involved in translation.
5. Eliminate incorrect options: RNA polymerase does not add amino acids to a polypeptide chain (translation) or unwind DNA for replication (a function of DNA helicase). Its primary function is synthesizing RNA from a DNA template.