Is this right

[jjfptl]

Hi,
I have a problem in genetics and I was wondering if it is correct, I am pretty sure this is right, just want to make sure:

Mutants 1, 2, 3, and 4 were analyzed and each was found to accumulate one compound (A - D), as indicated in the following table.
Mutant Accumulation
1 A
2 B
3 D
4 D

The pathway for phenylalanine biosynthesis is given below. Place mutants 1,2,3 and 4 in the pathway to show the reaction each gene catalyzes.

X -> R -> B -> A -> D -> phenylalanine

ANSWER : X -> R (2) -> B (1) -> A (3,4)-> D -> phenylalanine

and is this because: if mutant 1 accumulates A then enzyme B-A-lase is mutant 1, R-B-lase is mutant 2, A-D-lase is mutant 3 and 4. and they all have enzymes to synthesis of phenylalanine.

Just want to make sure i am understanding this. Thanks all

[mith]

If mutant 1 has inactive form for A->D enzyme, does that mean A accumulates since it cannot be further processed?

[jjfptl]

Did I confuse something here?

Now I think I may be lost.

[mith]

You said

if mutant 1 accumulates A then enzyme B-A-lase is mutant

However, if B->A is mutant, doesn't that mean that it accumulates B, since it cannot further process it into A?