Negative Regulation of Lac Operon — NEET Biology
📚 Practice ConceptRegulation of lac operon by repressor is referred to as negative regulation. Lac operon is under control of positive regulation as well, but it is beyond the scope of discussion at this level.
Which of the above statements are correct regarding the regulation of the lac operon? S1: The i gene is responsible for the constitutive synthesis of the repressor protein. S2: When lactose is absent, the active repressor binds to the operator, physically blocking RNA polymerase access to the promoter. S3: Lactose or allolactose serves as an inducer by binding to the repressor, which then dissociates from the operator. S4: The lac operon is primarily regulated by positive control mechanisms involving the repressor protein. S5: The structural genes (z, y, a) of the lac operon are transcribed into separate mRNA molecules. S6: The presence of glucose in the medium promotes the transcription of the lac operon when lactose is also available.
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