Question

The lac operon consists of several genes that encode enzymes required for metabolizing lactose. The expression of the lac operon is regulated by the presence of lactose and glucose.

1) describe the regulation operon when the level of glucose is high and the level of lactose is low

Answer 1

When glucose level is high and lactose level is low then very little transcription of lac operon take place because in presence of little lactose repressor bind with lactose and repressor does not bind to operator hence RNA polymerase binds to promoter due to which  little expression of operon take place but presence of glucose prevent formation of cAMP which bind with CAP to form CAP -cAMP complex that is bind on operator and  essential for three structural mRNA gene expression. So in high gluucose and low lactose very low expression of lac operon.