Jacob and Monad studied lactose metabolism in E.Coli and proposed the operon concept. The operon concept is applicable for:

Step-by-step solution

Regulation of transcription in prokaryotes typically involves an operon, such as the lac operon in E. coli. The lac operon is regulated by proteins that behave differently depending on whether lactose is present or absent. Related Theory When E.coli is exposed to both lactose and glucose, the organism first metabolise glucose and then temporarily cease to grow until the genes of lac operon become included to provide the ability to metabolise lactose.