The basic backbone of proteins are amino acids, and there are 20 different amino acids that synthesize proteins. The amino acids that make up proteins include glycine, alanine, valine, leucine, isoleucine, phenylalanine, proline, tryptophan, serine, tyrosine, cysteine, methionine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine. The alpha carbon above each amino acid is attached to a hydroxyl group, a hydrogen atom, an amino group and a side chain R group. In total, proteins are made up of three layers. If the structure changes, the protein becomes denatured. Proteins can improve the body’s immunity and are indispensable for many tissues and organs in the human body. If there is a lack of protein, it can easily lead to a decline in the body’s resistance and cause the body to fall ill.