AP BIOLOGY

Detailed explanation-1: -Promoter sequences are DNA sequences that define where transcription of a gene by RNA polymerase begins. Promoter sequences are typically located directly upstream or at the 5’ end of the transcription initiation site.

Detailed explanation-2: -A promoter is a short region of DNA (100–1, 000 bp) where transcription of a gene by RNA polymerase begins. It is typically located directly upstream or at the 5′ end of the transcription initiation site.

Detailed explanation-3: -Transcription typically initiates at a defined position, the transcription start site (TSS), at the 5ʹ end of a gene, which we refer to as the gene start. The TSS is embedded within a core promoter, which is a short sequence encompassing  50 bp upstream and  50 bp downstream of the TSS (Fig. 1a).