Final answer:
A promoter is a region at the beginning of a gene that initiates transcription by binding RNA polymerase and triggering the start of transcription. It is located upstream of the gene sequence and does not code for a protein.
Step-by-step explanation:
A promoter is a region at the beginning of a gene that initiates transcription. It is a particular sequence of nucleotides that triggers the start of transcription. The promoter is responsible for binding RNA polymerase, positioning the enzyme at the transcription start site, and initiating the unwinding of the DNA double helix for RNA synthesis. It is located upstream of the gene sequence and does not code for a protein.