How would you describe the effect a repressor has on the lac operon when lactose is present.?
1 Answer
Aug 1, 2016
In that situation the repressor has no effect.
Explanation:
The lac operon is an ingenious genetic system bacteria use for the production of metabolism and transport of lactose. Three genes in this operon are regulated together in a very efficient way.
In the absence of lactose the repressor binds to a certain region (the operator) of the operon. This inhibits transcription of the operon, because RNA polymerase can't bind.
In the presence of lactose the repressor is inactivated. A molecule similar to lactose (allolactose) binds to the repressor releasing it from the operator. Now the RNA polymerase can bind to start transcribing the genes.
This way the genes are only expressed when needed!