Regulation
Step-by-step explanation:
Operons are the structural unit of gene organisation
If product of regulatory gene binds to the upstream of promoter and induce expression of operon genes, system is called positively controlled whereas if product of regulatory gene binds to the operator and prevents expression of operon genes, system is called negatively controlled
An inducer binds to the repressor and induce conformational changes causing dissociation of repressor from operator therefore in absence of repressor RNA Polymerase binds to the promoter and starts transcription of genes
In some cases, A co-repressor binds to the repressor and activate it as a result activated repressor binds to the operator and prevent binding of RNA Polymerase thus blocks transcription of structural genes