BIOTECHNOLOGY

They are single cell organisms and they had limited source of energy. So, it is very important for them to use the limited energy in very efficient manner. They can’t take the risk of wasting energy running constitutive gene expression which is quite not necessary at particular set of environmental conditions. If we talk about, lac operon. let's say, in first set of environmental condition, i am getting glucose in the medium directly, so it will be total waste of my energy if i turn the operon on ( In the presence of glucose, the   lac   repressor   halts production of the enzymes encoded by the   lac   operon, the   catabolite activator protein   (CAP), required for production of the enzymes, remains inactive, and   EIIAGlc   shuts down lactose permease to prevent transport of lactose into the cell). In the second case, when there is no direct availability of preferable energy sources, like glucose, and there is only lactose in the mediu...