Answer:
Transcription of the trp operon is decreased when tryptophan interacts with the trp repressor. The trp repressor is a protein that binds to the operator sequence of the trp operon and blocks RNA polymerase from transcribing the genes for tryptophan synthesis. When tryptophan levels are high, tryptophan binds to the trp repressor and activates it, causing it to attach to the operator and repress transcription. When tryptophan levels are low, tryptophan dissociates from the trp repressor and inactivates it, allowing transcription to proceed
Step-by-step explanation: