Final answer:
A promoter is a DNA sequence onto which the transcription machinery binds and initiates transcription. The -10 and -35 regions upstream of the initiation site contain two promoter consensus sequences that are similar across all promoters and various bacterial species.
Step-by-step explanation:
A promoter is a DNA sequence onto which the transcription machinery binds and initiates transcription. In most cases, promoters exist upstream of the genes they regulate. At the -10 and -35 regions upstream of the initiation site, two promoter consensus sequences are similar across all promoters and various bacterial species. The -10 consensus sequence, called the -10 region, is TATAAT. The -35 sequence is recognized and bound by σ.