Fig. 1
Schematic representation of the six different classes of lipids. a Glycerophospholipid. R 1 represents a fatty acyl or alkyl groups. R 2 and R 3 depict a fatty acyl group and a polar group, respectively. b Glycerolipid. R 1 represents a fatty acid while R 2 and R 3 can be a fatty acid or a hydroxyl group. c Steroid based lipid. d Glycolipid. The lipid anchor can be a glycerophospholipid or a sphingolipid. e Sphingolipid. R 1 and R 2 represent a polar group and a fatty acyl group, respectively. f Free fatty acid