Question

Which Type of Operon Is an Inducible One?

Answer 1

Lac operon

1. Gene regulation in prokaryotes can be explained with the help of the Lac Operon model.
2. Here the alteration in physiological and environmental conditions can be observed leading to an alteration in expression in prokaryotes.
3. It was observed by Jacob and Monod.
4. The lac operon consists of:

• Regulatory gene i – It codes for the repressor protein.
• z gene – It codes for beta-galactosidase, which catalyzes the hydrolysis of lactose into glucose and galactose.
• y gene – It codes for permease which regulates the lactose permeability in the cell.
• a gene – It codes for transacetylase which assists the enzyme beta-galactosidase.

5. Operon contains multiple structural genes, which are regulated by a single promoter and operator.

6. Inducible operon is the one that is switched on only when there is an inducer present.

7. Lac operon is an example of an inducible operon, which is switched on in the presence of lactose or allolactose, which act as an inducer.

8.They bind to the repressor protein thereby preventing the binding of the repressor to the operator.

9. It makes the promoter site accessible for RNA polymerase to initiate transcription.