What are the genetic components of an operon and how do they control transcription?

What are the genetic components of an operon and how do they control transcription?

Operons are made of a promoter, an operator, and the structural genes. The promoter is the region where RNA polymerase is able to bind and start transcription. The operator is like the control switch for an operon. It is the place where the repressor protein can bind to prevent transcription. When the cell is in need of the proteins coded by the operon, the repressor releases the operator, allowing RNA polymerase to bind to the promoter and proceed with transcription. The structural genes are the genes that actually code for the protein products in the operator.

In biotechnology, specific promoters that respond to different chemicals can be used to express certain genes. Scientists can splice together the promoter and operator for the Lac operon to other genes they want to express. They insert the entire construct into a cell. The genes of interest can then be turned on or off by the natural regulator for the Lac operon, lactose.