Learn what molecules compose jaundice. The hemoglobin molecule is composed of two parts. These are: a heme portion and a gobin portion. The gobin portion is a polypeptide that is composed of amino acid chains.The important part of the hemoglobin molecule for our discussion is the heme portion of the hemoglobin.hus accumulation of bile and bilirubin in particular in the blood causes a type of jaundice that is caused by an obstruction in the biliary canals itself. In this type of jaundice the liver can function normally.