Question

Which of the following acts as a co-repressor in tryptophan operon?

• A. tryptophan
• B. tyrosine
• C. glucose
• D. lactose

Answer 1

Answer:

A. tryptophan

• Unlike lactose operon which is an inducible operon, the tryptophan operon is a repressible operon.

• Presence of tryptophan prevents the transcription of synthesis machinery requisite for the production of tryptophan by the cell.

• Tryptophan in this case is therefore a co-repressor.