Chemical bonds in lipids. (a)The ester (b)The ether (c)Isoprene.异戊 linkage as found in linkage of 二烯，the parent the lipids of structure of the Bacteria and lipids from hydrophobic side Eukarya. Archaea. chains(R)of archaeal lipids. -0-& By contrast,in R lipids of Bacteria H2C-0-C-[R and Eukarya,R are fatty acids. HC-O-C- -R HC —C-R CHg H2C-0- H2C-C H2C=C-=CH2 (a) (b) (cChemical bonds in lipids. (a) The ester linkage as found in the lipids of Bacteria and Eukarya. (b) The ether linkage of lipids from Archaea. (c) Isoprene异戊 二烯, the parent structure of the hydrophobic side chains (R) of archaeal lipids. By contrast, in lipids of Bacteria and Eukarya, R are fatty acids