Define Operon In Biology - What is Tryptophan Operon? Definition, Structure ... : These sugars, such as lactose and glucose , require different transcription of the lac operon normally occurs only when lactose is available for it to digest.
Diagram of an operon. At one end is a regulatory gene; the operon proper begins further down. The operon is composed of a promoter, an operator, and structural genes (in this case 4, labeled A – D). Transcription produces a single mRNA strand that contains all the structural genes. Translation of this single mRNA produces 4 different proteins (A, B, C, D).
