Protein structure

Proteins are made up of polymers of amino acids. The amino acids are joined together by peptide bonds in a condensation reaction. This type of reaction is catalysed by the ribosome in the cytoplasm and releases a water molecule. There are four levels of protein structure. The primary structure is the linear sequence of amino acids in a polypeptide chain.(1)

(1) http://www.chemguide.co.uk/organicprops/aminoacids/proteinstruct.html