Figure 16.3 Above Is a Metabolic Pathway for the Synthesis of an of an Amino

Multiple Choice

Figure 16.3
Above is a metabolic pathway for the synthesis of an amino acid E) , without which an organism could not live. Enzymes are represented by numbers, and substrates by letters. Use this figure for the next questions.
-Refer to the figure above. If an organism is given E in their diet, they survive. However, if the same organism is given only substrate A, B, C, or D in their diet, they die. Which of the enzymes is most likely defective?

A) Enzyme 1
B) Enzyme 2
C) Enzyme 3
D) Enzyme 4