Final answer:
The repressor protein binds to the operator region of the lac operon to turn off the lac operon genes in E. coli. The lac operon genes can be found in the bacteria E. coli and their purpose is to regulate the metabolism of lactose. The lac operon is active when lactose is present and glucose is low, allowing E. coli to produce enzymes for lactose metabolism.
Step-by-step explanation:
The lac operon is a regulatory system found in the bacteria Escherichia coli (E. coli). It consists of three genes - lacZ, lacY, and lacA - which encode enzymes involved in the metabolism of lactose. When glucose is present in sufficient amounts, a repressor protein binds to the operator region of the lac operon, preventing transcription of the genes. This effectively 'turns off' the lac operon genes.
In the absence of glucose, the repressor protein is unable to bind to the operator region, allowing the lac operon genes to be transcribed. However, when lactose is also absent, a lack of the inducer molecule prevents full activation of the lac operon. The inducer molecule, allolactose, binds to the repressor protein and prevents it from binding to the operator, thus allowing transcription of the lac operon genes to occur.
The lac operon is found in the bacteria E. coli and its purpose is to regulate the metabolism of lactose. When lactose is present in the environment and glucose is low, the lac operon allows E. coli to produce enzymes that can break down lactose for energy. In the presence of glucose or the absence of lactose, the lac operon is repressed and the genes are silent.