What signals RNA polymerase to stop transcription and detach from DNA?

• A. Promoter
• B. Start codon
• C. Anticodon
• D. Terminator sequence

Answer: (D)

Stopping transcription is controlled by a terminator sequence in the DNA. This region marks where RNA polymerase should end RNA synthesis and release the RNA transcript from the DNA template. In many bacteria, termination occurs because the nascent RNA forms a GC-rich hairpin followed by a short run of uracils, which causes the RNA polymerase to pause and dissociate from the DNA. Some systems also involve a separate factor like Rho that helps terminate transcription, but the key signal is the terminator sequence that designates the end of the transcript. The other options are related to initiation or processing: a promoter is where transcription begins, a start codon signals the start of translation in mRNA, and an anticodon is part of tRNA that recognizes mRNA codons.