Which of the following amino acids is not one of the 20 common amino acids found in cells?
A)leucine
B)isoleucine
C)glutamine
D)proline
E)pyrrolysine

Question

Quizplus · Accepted Answer

Pyrrolysine is not one of the 20 standard amino acids encoded directly by the universal genetic code. It is considered a special case, found in some archaea and bacteria, incorporated into proteins by a unique mechanism.

Which of the Following Amino Acids Is Not One of the 20