Question

In the early 1930’s william rose fed laboratory rats a mixture of all 19 amino acids known to be present in proteins. he observed that his rats lost weight. this observation led to the discovery of ______ as the 20th amino acid found in proteins.

Answer 1

If these were the missing choices:
A)Gly
B)Ala
C)Tyr
D)Asn
E)Thr

The answer is E.) Thr.

Thr stands for Threonine. It is a polar amino acid. Its side chains are also hydroxylic.
Aside from promoting normal growth by helping maintain proper protein balance in a body, Threonine also supports cardiovascular, central nervous, immune system, and liver function.