Final answer:
An operon is a unit of genetic regulation found in prokaryotic cells, and its gene transcription is regulated by activators, inducers, and repressors. Activators enhance the binding of RNA polymerase to initiate transcription, inducers prevent repressor proteins from binding to the operator region, and repressors inhibit the binding of RNA polymerase.
Step-by-step explanation:
The operon is a unit of genetic regulation found in prokaryotic cells. It consists of a group of genes that are transcribed together as a single mRNA molecule. The gene transcription in an operon is regulated by various components, including activators, inducers, and repressors.
An activator is a protein that binds to the promoter region of an operon and enhances the binding of RNA polymerase to initiate transcription. It helps in promoting the expression of genes in the operon. For example, in the lac operon in E. coli, the cAMP-CRP complex acts as an activator.
An inducer is a small molecule that binds to a repressor protein and prevents it from binding to the operator region of an operon. This induces the transcription of genes in the operon. In the lac operon, lactose acts as an inducer by binding to the lac repressor and allowing RNA polymerase to bind to the promoter.
A repressor is a protein that binds to the operator region of an operon and inhibits the binding of RNA polymerase to initiate transcription. It helps in repressing the expression of genes in the operon. In the trp operon in E. coli, the tryptophan-bound trp repressor acts as a repressor.