Q. E coli cells with a mutant z gene of the lac operon cannot grow in medium containing only lactose asthe source of energy because (AIPMT - 2005) (Solved)
1. the lac operon is constitutively active in these cells
2. they cannot synthesize functional beta galactosidase
3. in the presence of glucose E Coli cell do not utilize lactose
4. they cannot transport lactose from the medium into the cell
- b. they cannot synthesize functional beta galactosidase