Question: Four auxotrophic mutant strains of E. coli (1, 2, 3, 4) are each blocked at a different step of t…

Four auxotrophic mutant strains of E. coli (1, 2, 3, 4)
are each blocked at a different step of the same metabolic pathway.
This pathway involves compounds L, M, N, O, and P. Each of these
compounds is tested for its ability to support growth of mutant
strains, with the results given below.
(+= growth, ^__ = no growth)

a. Give the order of the compounds in the metabolic pathway and
indicate the specific step that is blocked in each mutant
strain.

b. Several sets of double mutations were produced. For example,
double mutant 1, 2 has mutant forms for enzymes 1 and 2. Pairs of
these double mutations were combined in partial diploids. Would a
partial diploid consisting of each of the following pairs of double
mutations grow on minimal medium (without supplementation with L,
M, N, O, P)?

1,3 and 3,4

1,2 and 3,4

2,4 and 1,2

Explain