Question 2. (8 points) In E. coli, tryptophan synthesis is
partially regulated presence or absence of tryptophan in the growth
medium. Answer the follow questions about the regulation of
expression of the tryptophan biosynthetic encoded in the tryptophan
operon.

a. Is tryptophan an activator or repressor of the expression of
the operon?

b. Is this different than the effect of the presence of lactose
on expression operon? Why or why not?

Describe how each of the following mutations would change the
wild type re the operon.

c. Mutation of the G in the start codon (AUG) In the leader
sequence open frame to a C.

d. Deletion of all tryptophan codons in the leader sequence open
reading f

e. Mutation of all the tryptophan codons in the leader sequence
open read codons for alanine.