How Many Naturally Occurring Amino Acids are Commonly Found in Proteins

Question

How many naturally occurring amino acids are commonly found in proteins?
A) 10
B) 20
C) 25
D) 100

Accepted Answer

There are 20 naturally occurring amino acids commonly found in proteins. These 20 amino acids are characterized by a common backbone structure, but differ in the side chain or R group that gives each amino acid its unique properties.