Genes have many regulatory sites that control gene expression, one of these is called the enhancer.

Which choice best describes the enhancer site?

a) The enhancer site is a distal control site many nucleotides upstream from the promoter site, and activates the initiation complex of transcription.

b) The enhancer site is only found in operons of a prokaryotic cell.

c) The enhancer site is part of the termination sequence that tells RNA polymerase to stop the process of transcription.

d) The enhancer site is part of the promoter region that allows transcription factors to bind, allowing RNA polymerase to bind.

a) The enhancer site is a distal control site many nucleotides upstream from the promoter site, and activates the initiation complex of transcription.

Explanation:

Enhancers are the regulatory DNA sequences that are generally located quite away from the coding regions of a gene. These sequences are mostly present upstream of promoter sequences. Enhancers regulate the gene expression by stimulating the formation of an active transcription initiation complex and thereby, increase the rate of RNA synthesis. Enhancers also serve as the binding site for specific regulatory proteins. These proteins bound to the enhancers then activate transcription by interacting with the proteins bound to the promoters.