The most striking chemical differences between Archaea membrane lipids and lipids of living organisms are as follows. The former contain (1) 2,3-di-O-difytanyl-sn-glycerol instead of 1,2-diacyl-sn-glycerol, (2) ether bonds instead of ester bonds, (3) isoprenoid chains instead of fatty acids, (4) branched isoprenoids. The structure of Archaea membranes is also unique. Lipid vesicles prepared from archaeal lipids (archaeosomes) are more stable than liposomes and are useful for medical and biotechnological applications.