Describe the structure of proteins in terms of Primary, Secondary, Tertiary and Quaternary structures

The primary structure comprises of the original sequence of amino acids resulting in a polymer of amino acids. These are joined to adjacent amino acids through by peptide bonds, formed by condensation reactions through the removal of an H2O molecule. The secondary structure is the folding of the polypeptide chain due to hydrogen bonding into alpha helix or a beta pleated sheet. Tertiary structures include the 3-D specific folding due to hydrogen bonding as well as ionic bonds amongst charged amino acid side groups, and disulfide bridges in amino acids that contain sulfur within their variable side chains. Finally, the quaternary structure is two or more polypeptide chains that come together to form the protein in its final form.