Phospholipids are a class of lipids and are a major component of all cell membranes as they can form lipid bilayers. Most phospholipids contain a diglyceride, a phosphate group, and a simple organic molecule such as choline; one exception to this rule is sphingomyelin, which is derived from sphingosine instead of glycerol. Amphipathic character The 'head' of a phospholipid is hydrophilic (attracted to water), while the hydrophobic 'tails' repel water. The hydrophillic head contains the negati… (More on Phospholipids)