E. coli prefers glucose as an energy source when both glucose and lactose are available. Lactose is an alternative energy source that can be used if glucose is absent. The overall rate of messenger RNA synthesis from the lac operon is indirectly regulated by the concentration of glucose in the cell. cAMP is the second messenger used directly in the regulation of lac operon expression in response to changing levels of glucose in E. coli and is involved in the positive regulation of the lac operon. In a low glucose environment, cAMP accumulates and binds to the allosteric site on the cAMP receptor protein. a transcription activator protein. The protein assumes its active shape and binds to a specific site upstream of the lac promoter.
A. TRUE
B. FALSE