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Explain the role of regulartory gene in a lac operon. Why is regulation of lac operon called as negative regulation?

 

 

 

 
 
 
 
 

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The lac operon consists of one regulatory gene (the i gene) . The i gene codes for the repressor of the lac operon.

The repressor of the operon is synthesised (all-the-time – constitutively) from the i gene. The repressor protein binds to the operator region of the operon and prevents RNA polymerase from transcribing the operon.

In the presence of an inducer, such as lactose or allolactose, the repressor is inactivated by interaction with the inducer. This allows RNA polymerase access to the promoter and transcription proceeds. Regulation of lac operon by repressor is referred to as negative regulation.

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Priyanka Kumari

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