An operon is a part of DNA that functions as a gene regulatory unit in transcription.
(a) Regulatory gene : This gene controls the operator gene. This produces a protein substance known as represser which combines with the operator gene to stop its function.
(b) Operator : It controls the functioning of structural genes which are expressed when operate, gene is turned on by inducer and not expressed when operates is turned off by repressor.
(c) Promoter : It is the site at which the RNA polymerase binds and reaches the structural genes for the transcription of mRNA to start.
(d) Structural genes : These genes produce mRNA which synthesize the specific proteins such as enzyme regained for metabolism of Lactose.
