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MHT CET Medical202624 April 2026Morning ShiftBiologyMolecular Basis of InheritanceActual

The repressor protein in lac operon is produced by the action of ________.

Options

  1. Aoperator gene
  2. Bregulator gene
  3. Cpromoter gene
  4. Dstructural gene

Correct answer

B. regulator gene

Step-by-step solution

The lac operon consists of regulatory and structural genes. The regulator gene (i gene) codes for the repressor protein of the lac operon. This repressor protein binds to the operator region and prevents RNA polymerase from transcribing the structural genes. The operator gene is the site where the repressor binds. The promoter gene is the site where RNA polymerase binds to initiate transcription. The structural genes (z, y, and a) code for enzymes required for lactose metabolism. Answer: regulator gene

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