Inducer and repressor in lac operon :
Inducer : Lactose is the substrate for the enzyme beta-galactosidase, and it regulates switching on and off of the operon. It is termed as Inducer.
Repressor : The repressor of the operon is synthesized (all the time constitutively) from the gene. The repressor protein binds to the operator region of the operon and prevents RNA polymerase from transcribing the operon.
