Question

Explain working of lac-operon with diagrammatic representation:

Answer 1

Mechanism of lac operon :

• In the absence of inducer lactose, the regulator gene R produces a repressor protein which binds to the operator site and prevents transcription of structural genes.
• When inducer lactose is introduced in the medium, it binds to the repressor and prevents it from binding to the operator. The operator then induces the RNA polymerase to bind to the promoter and transcribe structural genes to form the mRNA from which the enzymes are formed.