Final answer:
The control of the trp operon involves repressive control and feedback inhibition. In repressive control, tryptophan binds to the trp repressor protein, preventing RNA polymerase binding and transcription. Feedback inhibition occurs when an excess of tryptophan blocks the first enzyme in the synthesis pathway.
Step-by-step explanation:
The control of the trp operon involves two mechanisms: repressive control and feedback inhibition.
In the repressive control mechanism, when tryptophan is present in the cell, it binds to the trp repressor protein, which then binds to the operator of the trp operon. This prevents the binding of RNA polymerase and stops transcription of the structural genes, leading to the inhibition of tryptophan synthesis.
In the feedback inhibition mechanism, when there is an excess of tryptophan in the cell, it allosterically inhibits the trp synthesis pathway. This occurs through rapid feedback inhibition, where tryptophan blocks the first enzyme in the pathway, effectively shutting down the synthesis of tryptophan.