Question

If E. coli were subjected to high levels of lactose and low levels of glucose, which of the following conditions would apply? Y = yes, N = no

A) lac repressor would be bound to the operator of the lac operon promoter

B) CAP protein would be bound to the CAP binding site adjacent to the lac operon promoter

C) cAMP levels would be low

D) the lac operon would be actively expressing the operon into separate mRNA molecules needed to synthesize the enzymes required for lactose metabolism

E) the trp operon would be necessarily activated.

Answer 1

A) No

When lactose is present then it binds to lac repressor to mak repressor inactive so repressor cannot binds to operator.

B) Yes

When Glucose conc is low, then cAMP conc is high which binds to CAP protein and both complex bings to promote region

C) No

Low glucose cannot degrades cAMP

D) Yes

When lactose is present and glucose is low conc or absent,lac operon switch on and synthesize mRNA

E) No

Lac operon has no connection with tryp operon as trp operon is for amino acid synthesis.

Thanks..!