. "The chemical reactions and pathways resulting in the formation of heparin, any member of a group of glycosaminoglycans of average Mr (6000-20000), consisting predominantly of alternating alpha-(1->4)-linked D-galactose and N-acetyl-D-glucosamine-6-sulfate residues." . . . . "heparin biosynthetic process" . "heparan sulfate biosynthetic process" . "heparin anabolism" . "heparin biosynthesis" . "heparin formation" . "heparin synthesis" . . .