Selenocysteine,N-formylmethionine and pyrrolysine are found in many proteins.These amino acids are considered standard amino acids along with 20 common amino acids because they
A)are incorporated into proteins from specific codons.
B)are formed by post-translational modifications.
C)play key roles in metabolism.
D)are precursors of other important amino acids.

Question

Quizplus · Accepted Answer

Selenocysteine, N-formylmethionine, and pyrrolysine are considered standard amino acids because they are incorporated into proteins from specific codons. These codons are recognized by specific transfer RNA molecules, and the amino acids are inserted into the growing polypeptide chain during protein synthesis.

Selenocysteine,N-Formylmethionine and Pyrrolysine Are Found in Many Proteins