PPT Slide
Spheres are not the only minimal surfaces. Minimal surfaces which are not closed can partition space into a labyrinth and such labyrinths are seen in membranes of living cells. These internal cell walls are made up of amphiphilic molecules, called lipids, like the surfactants that create the skin of a soap bubble. However, in the soap bubble, the water soluble heads point towards each other, constraining the trapped layer of fluid to be very thin. With lipids, the tails point towards each other, allowing the water soluble heads to face a large region of the fluid.