Which of the following numbers is the total number of amino acids?

Which of the following numbers is the total number of amino acids?

• A. 20
• B. 18
• C. 22
• D. 24

Answer: (A)

Proteins are polymers built from amino acids, and there are twenty standard amino acids that make up the vast majority of proteins across organisms. These twenty are encoded by the genetic code and are incorporated during translation by the ribosome, providing the diverse chemical properties needed for proper folding and function. While there are rare instances where two additional amino acids, selenocysteine and pyrrolysine, are used in specialized cases, the canonical count taught in most biology courses is twenty. The other numbers listed don’t reflect the common, standard set.

Proteins are polymers built from amino acids, and there are twenty standard amino acids that make up the vast majority of proteins across organisms. These twenty are encoded by the genetic code and are incorporated during translation by the ribosome, providing the diverse chemical properties needed for proper folding and function. While there are rare instances where two additional amino acids, selenocysteine and pyrrolysine, are used in specialized cases, the canonical count taught in most biology courses is twenty. The other numbers listed don’t reflect the common, standard set.