16.3.1—Structural genes vs regulatory genes

A structural gene encodes a functional product such as an enzyme or structural protein. A regulatory gene encodes a product or control sequence that changes the expression of other genes.

Separating product from control lets cells adjust pathway activity without changing every structural gene. Regulation can act at transcription, RNA processing, translation or protein activity.

A regulatory protein can bind near a structural gene and prevent RNA polymerase from transcribing an enzyme that is not currently needed.

‘Regulatory’ does not mean the gene has no product. It means its product or sequence influences expression of another gene or set of genes.