NEETZoologyMolecular Basis of Inheritance
What is the purpose of the operator and repressor in the lac operon?
Options
- ATo synthesize RNA polymerase
- BTo bind to the promoter region
- CTo bind a transcription factor
- DTo repress the expression of beta-galactosidase
Correct answer
D. To repress the expression of beta-galactosidase
Step-by-step solution
In prokaryotes, control of the rate of transcriptional initiation is the predominant site for control of gene expression. In a transcription unit, the activity of RNA polymerase at a given promoter is in turn regulated by interaction with accessory proteins, which affect its ability to recognise start sites. These regulatory proteins can act both positively (activators) and negatively (repressors). The accessibility of promoter regions of prokaryotic DNA is in many cases regulated by the interaction of proteins wit