Each variable group on an amino acid gives that amino acid specific chemical properties (acidic, basic, polar, or nonpolar). This gives each amino acid R group different chemical properties

The carboxyl group of one amino acid and the amino group of the incoming amino acid combine, releasing a molecule of water and creating the peptide bond.

Each amino acid is attached to another amino acid by a covalent bond, known as a peptide bond,

There are 20 genetically encoded amino acids available to the cell to build in proteins and all of these contain the same core sequence: N-C-C- where the first ("alpha") C will always carry the R group and the second will have a double (ketone) bond to oxygen

Each amino acid has the same core structure, which consists of a central carbon atom, also known as the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and a hydrogen atom.

Amino acids are the monomers that make up proteins.