When glucose is high, camp is low : cap doesn't bind the lac operator, and RNA polymerase doesn't bind the lac promoter.
Explanation:
The lac operon is a molecule responsible for the rapid transport of lactose in Escherichia coli, mainly, but it can be found in other bacteria. This molecule is essential to regulate several factors within the bacterial cell, however the main factor regulated by it is the availability of glucose and lactose in the environment. WWhen glucose is high, camp is low: cap doesn't bind the lac operator, and rna polymerase doesn't bind the lac promoter.
When glucose is high, cAMP is low; CAP does not bind the lac operator, and RNA polymerase does not bind the lac promoter. CAP is only active when glucose levels are low, which means the cAMP levels are high, and therefore the lac operon can only be transcribed at high rate when glucose is absent. The importance of this is that the bacteria only turns on the lac operon and start using lactose only after they have used up all the preferred energy source which is glucose.
