- A It binds directly to RNA polymerase to switch on its activity
- B It binds to the repressor protein, preventing it from binding the operator
- C It binds directly to the operator sequence itself to block transcription
- D It enzymatically degrades the repressor protein into inactive fragments
Correct answer: B. It binds to the repressor protein, preventing it from binding the operator
Explanation: Allolactose (the inducer) binds the repressor protein, changing its shape so it can no longer bind the operator; this allows transcription of the structural genes.
Concept context
DNA structure, replication, transcription, translation, the genetic code, and gene regulation (lac operon). The single most important chapter for NEET molecular biology.