In an E. coli strain the i gene gets mutated and its product cannot bind the inducer molecule. If the growth medium is provided with lactose, what will be the outcome?
- AOnly z gene will get transcribed
- Bz, y, a genes will be transcribed
- Cz, y, a genes will not be translated
- DRNA polymerase will bind the promoter region
Solution & Step-by-step Explanation
The i gene produces the repressor. Normally, the inducer (lactose/allolactose) binds the repressor to inactivate it, allowing transcription. If the mutated repressor cannot bind the inducer, it will remain permanently bound to the operator, blocking RNA polymerase. Thus, the structural genes (z, y, a) will not be transcribed or translated, regardless of whether lactose is present.