Question

3 Lac operon

a) what does the signal detect/respond to?

b) When is the signal on/off?

c) I the system inducible, repressible, or mixed?

d) Describe the system's response.

Answer 1

Ans.a.signal detect to the presence of lactose /allolactose by which the repressor bind so that it does not bind with the operator thats why structural gene causes production of enzyme mainly of betagalactosidase.

Ans.b.signal is on when lactose present or vice versa.

Ans.c.system is inducible only,because when lactose present then enzyme production start otherwise switch off.

Ans.d.when lactose present then switch on the lac operon by which lac-Z gene produce beta galactosidase enzyme by which lactose breaks into glucose and galactose hence system respond to produce these product.