The repressor protein requires the end product created by the enzymes of this operon for repression.

Question

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The trp operon is regulated by a repressor protein that requires the end product (tryptophan) created by the enzymes of the operon for repression. When there is sufficient tryptophan, it binds to the repressor protein and allows it to bind to the operator region, blocking transcription of the operon. If tryptophan levels are low, the repressor protein cannot bind to the operator region and transcription of the operon proceeds. In contrast, the lac operon is regulated using an inducible system, where the repressor protein is active in the absence of an inducer (such as lactose).

The Repressor Protein Requires the End Product Created by the Enzymes