Question

1. Use the statements below to fill in the blanks in the order they appear.
   When tryptophan is available in abundance for a long time, E. coli cells will ______________. When tryptophan levels rise temporarily, E. coli cells will ______________. _____
   When tryptophan levels temporarily drop, E. coli cells will ______________.

   1. turn off tryptophan synthesis at the enzymatic level via feedback inhibition.
   2. turn off tryptophan synthesis at the transcription level.
   3. turn off tryptophan synthesis at the enzymatic and transcription levels.
   4. turn on tryptophan synthesis at the transcription level.
   5. turn on tryptophan synthesis at the enzymatic level via feedback inhibition.

   	a.	1, 2, 3
   	b.	3, 1, 2
   	c.	4, 5, 1
   	d.	3, 1, 5
   	e.	2, 1, 4
   	f.	3, 4, 5

Answer 1

Option E

2, 1, 4.

Turn off tryptophan synthesis at the transcription level.

Turn off tryptophan synthesis at the enzymatic level via feedback inhibition.

Turn on tryptophan synthesis at the transcription level.

When tryptophan is abundantly available then the e.coli will turn off the synthesis.

If tryptophan is rised then the e.coli will turn off the operon. At the enzymatic level via feedback inhibition.

If tryptophan level is low then the e.coli will switch on the operon and synthesis of tryptophan is done.