Lipid membrane. Computer illustration showing the phospholipid membrane (centre) that surrounds cells (bottom). Cell membranes are composed of a bilayer of phospholipids that have hydrophilic ('water-loving') heads (spherical) and hydrophobic ('water-hating') tails. This causes them to align themselves with their tails pointing towards each other (away from any water), leaving the heads on the outside of the bilayer.
Model release not required. Property release not required.