Final answer:
The RNA polymerase binds to the promoter region to initiate transcription, marking the beginning of the gene where transcription is triggered. The promoter determines the correct location for RNA polymerase to start transcribing the DNA into mRNA.
Step-by-step explanation:
The region at which the RNA polymerase binds is the promoter region. The promoter is a specific DNA sequence that signals the start of transcription. This DNA sequence is located upstream of the coding region and marks the transcriptional start site, which is where RNA polymerase must bind to initiate the synthesis of messenger RNA (mRNA).
Initiation of transcription begins when RNA polymerase binds to the promoter. The enzyme then unwinds the DNA strands, allowing it to 'read' the bases in one of the strands to synthesize a complementary strand of mRNA. The promoter region is essential as it is not only the binding site for RNA polymerase but also determines which of the two strands will be transcribed, and it helps to position the enzyme correctly.