Sketch a schematic diagram of lac operon in switched on position. How is operon switched off? Explain.

Explanation

See. Q. 29. Set-III, Outside Delhi-2011.
In "switch of'' position, i gene which stands for inhibitor is transcribed. The repressor of the operon is synthesised from the gene.
The repressor protein in the absence of an inducer binds to the operator region of the operon and prevents RNA polymer ase from transcribing the protein.
Regulation by lac operon is referred to as negative regulation because the repressor binds to the op·erator for "switched off' operon.