When milk is present, the lactose repressor binds to the lac operon.
Is this true or false?
I think it is false.....?
TRUE
To determine if the statement is true or false, let's break it down and understand the concepts involved.
The lac operon is a genetic system found in bacteria that regulates the metabolism of lactose. It consists of three main components: the promoter, the operator, and the structural genes (lacZ, lacY, and lacA).
The lactose repressor is a protein encoded by the lacI gene, located nearby the lac operon. It acts as a regulatory protein that controls the expression of the lac operon. Normally, in the absence of lactose, the lactose repressor binds to the operator, preventing the transcription of the structural genes. This binding essentially shuts down the lac operon, suppressing the production of proteins involved in lactose metabolism.
When lactose is present, it acts as an inducer and binds to the lactose repressor. This binding causes a conformational change in the repressor, preventing it from binding to the operator. As a result, the lac operon is derepressed, allowing RNA polymerase to bind to the promoter and initiate transcription of the structural genes.
Based on this explanation, we can conclude that the given statement is false. The lactose repressor binds to the operator in the absence of lactose, not when milk is present.