How would lac operon operate in E. coli growing in a culture medium where lactose is present as source of sugar ?

(a) Explain the role of regulatory gene, operator and structural genes in lac operon when E. Coli is growing in a culture medium with the sources of energy as lactose.

How is lac operon ‘switched on’ in an E. coli cell?

This is not produced by E.coli in the lactose medium :

E. coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because

Given above is the schematic representation of lac operon of E.coli. Explain the functioning of this operon when lactose is provided in the growth medium of the bacteria.

The wild type E. coli cells are growing in normal medium with glucose. They are transferred to a medium containing only lactose as sugar. Which of the following changes take place ?

(b) Mention what would happen if lactose is withdrawn from the culture medium.

Look at the figure depicting lac operon of E. coli. What could be the series of events when an inducer is present in the medium in which E. coli is growing?

Why does the lac operon shut down some time after the addition of lactose in the medium where E.coli was growing ? Why low level expression of lac operon is always required ?

In E.coli, lac operon is induced by