Fig. 1.

The chemical structures and schematic diagram of the three membrane phospholipids depicting the charge distribution and headgroup size. The more or less cylindrical PC carries a zwitterionic headgroup on a glycerol with two fatty acyl chains (diacylglycerol), usually one unsaturated (bent). PE has a small headgroup and a conical shape and creates a stress in the bilayer. PA carries a negative charge and it also has a similar headgroup size as PE