Final answer:
The promoter sequence in DNA is a specific DNA sequence that signals the beginning of a gene and is important for initiating transcription. It is located upstream from the genes it regulates and has a critical role in controlling gene expression.
Step-by-step explanation:
A promoter is a specific DNA sequence that signals the beginning of a gene. It is the region of DNA to which RNA polymerase binds to initiate transcription. Promoters are located upstream of the genes they regulate and play a crucial role in controlling gene expression. The specific sequence of a promoter determines how frequently and under what conditions a gene is transcribed.