NEET2015ZoologyMolecular Basis of InheritanceActual
Gene regulation governing lactose operon of E. coli that involves the lac I gene product is:
Options
- APositive and inducible because it can be induced by lactose
- BNegative and inducible because repressor protein prevents transcription
- CNegative and repressible because repressor protein prevents transcription
- DFeedback inhibition because excess of β - galactosidase can switch off transcription
Correct answer
B. Negative and inducible because repressor protein prevents transcription
Step-by-step solution
In negative regulation, a repressor molecule binds to the operator of an operon and terminates transcription. The lac operon is a negatively controlled inducible operon, where the inducer molecule is allolactose.