N the reverse is a hydrolysis reaction j a water molecule is used to break the covalent bonds between the monomers. N most molecules are polymers and are present in all organisms in roughly the same proportions. N function of proteins: structural support, protection, transport, catalysis, defence, regulation, and movement. N proteins are made from 20 different amino acids. N all proteins consist of a polypeptide chain j single unbranched chain of amino acids. N the composition of a protein: relative amounts of each amino acid present. N the sequence of amino acids in the chain determines the protein structure and function. N amino acids have carboxyl and amino groups j they function as both acid and base. zh-carbon is asymmetrical; therefore there are two kinds of amino acids l- and. N the side chains or r-groups also have functional groups. N amino acids are grouped based on these side chains: electrically charged.