When are the structural genes in the tryptophan operon transcribed?
1)Tryptophan is in abundance in the environment.
2)Tryptophan is absent from the environment.
3)Tryptophan is present in low amounts in the environment.
A) 1
B) 2
C) 3
D) 1 and 3
E) 2 and 3

Question

Quizplus · Accepted Answer

The tryptophan operon is transcribed when tryptophan is absent from the environment or present in low amounts. This is because the operon is part of a repressible system, where the presence of high levels of tryptophan activates a repressor that stops transcription.

When Are the Structural Genes in the Tryptophan Operon Transcribed