Genetics : Lac Operon

What is it and how does it work?

One day, we (prokaryotes) realise that our normal food, rice/bread/wheat, (glucose) is no more!! And the only thing we can do now, is to eat delivered Hot Turkey (lactose) !

Now, the delivered Hot Turkey is outside our doorstep, but the thing is.. we are unable to just take in the Hot Turkey and eat it just like that, because it is sizzling Hot and super big!

What we need are gloves (lactose permease) which we can use to help us bring in the Hot Turkey and then knife (Beta-galactosidase) cut it up. But we do not have gloves or knife! Luckily..we can order them online, using our computer (gene).
Therefore, imagine our computer (gene), which we can order :
-gloves (lactose permease) , to bring in that Hot Turkey from outside our door
-knifes (Beta-galactosidase) , to cut up that turkey so we can eat it

But the thing is, we can't access our computer to order that glove and knife. That is because our computer is blocked by a password (Lac Repressor Protein), and it also has no power supply (low cAMP and therefore inactive CAP).

Therefore, that is the Lac Operon, which is a gene, on the prokaryotes, that composes of a) the codes to make proteins for lactose metabolism and also b) the regulatory region for those proteins.
Just like our computer, which composes of a) the order form for the tools needed to bring in and cut up that Hot Turkey, and also b) what determines whether we get to order the gloves and knife, which is the password, and the power supply of the computer!

And so how then do we get to order the tools needed so that we can bring in and cut up the Hot Turkey?
1) When our computer detects that there are Hot Turkeys around our house (lactose present), it automatically allows us to access it, without a password! (prevents repressor binding)
2) When our computer detects that we really do not have normal food left (low glucose), it automatically turns on its power supply (increase cAMP and activate CAP), so we can use it to order gloves and knife to bring in and cut up that Hot Turkey!

And that, is an analogy on how the Lac Operon works in the Prokaryotes. =)