How does RNA polymerase know where to start transcribing a gene into mRNA?

• A. It begins transcription at the start codon.
• B. It randomly selects a starting point on the DNA strand.
• C. It starts at the terminator sequence of the gene.
• D. It binds to the promoter region of the gene.

Answer: (D)

Verified step by step guidance

1. Understand the role of RNA polymerase: RNA polymerase is an enzyme responsible for transcribing DNA into RNA. It needs a specific starting point to begin this process.
2. Learn about the promoter region: The promoter is a specific sequence of DNA that signals the RNA polymerase where to start transcription. It is located upstream of the gene to be transcribed.
3. Recognize the importance of the promoter: The promoter region contains specific sequences that are recognized by transcription factors and RNA polymerase, facilitating the binding of RNA polymerase to the DNA.
4. Distinguish between different DNA sequences: The start codon is involved in translation, not transcription. The terminator sequence signals the end of transcription, not the start. The promoter is the correct starting point for transcription.
5. Conclude with the correct process: RNA polymerase binds to the promoter region of the gene, initiating the transcription of DNA into mRNA.