In the fungus Neurospora, a metabolic pathway synthesizes the amino acid Z (which is essential for its survival) from the precursor W. The intermediates X and Y are also produced in this pathway
The enzymes E1, E2, and E3 catalyze three reactions in the process, as follows:
E1 E2 E3
W ? X ? Y ? Z
X-ray radiation can be used to create a mutant strain of Neurospora that has a defective gene sequence for E2.
Based on this scenario, the mutant strain will survive on media that contain
A) only Z.
B) only X.
C) only W or X.
D) only Y or Z.
E) W, X, Y, or Z.
D
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