RNA Polymerase Binds to the Template Strand in Transcription

Steps:

• Recall that transcription synthesizes RNA from a DNA template.
• Identify DNA strands: one serves as the template (antisense), the other as coding (sense).
• Understand RNA polymerase unwinds DNA and reads the template strand 3' to 5' to build complementary RNA.
• Confirm binding occurs on the template strand to ensure accurate RNA sequence.

Why D is correct:

• By definition, the template strand is the DNA sequence directly read by RNA polymerase, providing the base-pairing instructions for RNA synthesis.

Why the others are wrong:

• A. Leading strand refers to continuous DNA synthesis in replication, not transcription binding.
• B. Lagging strand involves discontinuous replication fragments, irrelevant to RNA polymerase.
• C. Non-transcribed strand is the coding strand, which RNA polymerase does not bind to for reading.

Final answer: D