Question

In bacterial cell, the tryptophan operon encodes the genes needed to synthesize tryptophan. When the concentration of tryptophan inside the cell is high:

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a
It inactivates the tryptophan repressor allowing transcription of the tryptophan operon
b
It inactivates the tryptophan repressor which shuts down the tryptophan operon
c
It activates tryptophan repressor which shuts down the tryptophan operon

Answer 1

High intracellular concentrations of tryptophan activate the repressor, shutting down the tryptophan operon to prevent the synthesis of more tryptophan.

Step-by-step explanation:

When the concentration of tryptophan inside a bacterial cell is high, it activates the tryptophan repressor, which shuts down the tryptophan operon. Tryptophan serves as a corepressor by binding to the trp repressor protein, enabling it to bind to the operator sequence. This binding prevents RNA polymerase from transcribing the genes necessary for tryptophan synthesis, thereby halting the production of enzymes that would make more tryptophan.