... it, and another group which is known as a side chain or R-group. This side chain is of particular significance, as it provides the diversity of amino acids. These side chains vary in complexity, and the most basic is found in the amino acid glycine, which consists of only one hydrogen atom. Proteins make up the majority of a cells mass, minus the water, and are essential in almost everything the cell does. They are extremely complex macromolecules, and each type of protein has its own individual three dimensional shape, but are all made up of the same 20 amino acids in different arrangements. Amino acids are linked together in an unbranched chain by peptide bonds to form polypeptides. This bond is formed when the amino group of one amino acid is next to the carboxyl group of another and an enzyme is introduced to cause a condensation, or dehydration, reaction, ...

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