The R group is what makes amino acids different. It’s also called a side chain. The R group gives each amino acid its unique properties. It’s what separates each of the 20 amino acids.

Each of the 20 amino acids has a specific side chain, known as an R group, that is also attached to the α carbon. The R groups have a variety of shapes, sizes, charges, and reactivities.

Amino acids are characterized by their central carbon atom, known as the α-carbon, which is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain ...

Amino acids have different side chains (R groups), which give them different properties. Some of these side chains are big, some are small, some are hydrophilic (interact with water), and some are ...