1. Researchers have identified an E.coli strain having constitutive expression of camp. What would be the effect on lac operon expression in the following media? What if this mutant also contained an O^- mutation?
a. Glucose
b. Lactose
c. Glucose + Lactose
2. A mutant strain of E.coli has constitutive expression of the trp operon. How could this mutant phenotype result?
3. A mutant strain of E.coli expresses trp operon mRNA but still cannot synthesize trypophan. How could this mutant phenotype result?
4. Given the following data, what is the genotype of mutant X?
|
|
|
Relative
|
Level
|
Of
|
Trp
|
Enzymes
|
|
|
|
E
|
D
|
C
|
B
|
A
|
|
Mutant X
|
+ trp
|
30%
|
30%
|
30%
|
30%
|
0%
|
|
Mutant X
|
- trp
|
100%
|
100%
|
100%
|
100%
|
0%
|