Human cells and mouse cells fuse resulting in a cell called a heterokaryon . In a newly formed heterokaryon , half the surface displayed green fluorescence , the other half red . However, in less than an hour at 37 C , the red and green fluorescing surfaces became completely intermixed forming a ruddy brown color. This experiment revealed that a membrane protein can diffuse through a distance of several microns in approximately one minute. Fluidity of a Lipid Bilayer Depends on Its Composition and Temperature cis-double bonds produce kinks making fatty acids more difficult to pack together.
Cholesterol enhances the barrier properties , and prevents fatty acid chain crystallization .
Because negatively charged phosphatidylserine is in the inner monolayer, difference in charge between the two halves of the bilayer. Glycolipids Are Found on the Surface of Plasma Membranes Glycolipids are exclusively in the noncytoplasmic half of the lipid bilayer . Gangliosides contain oligosaccharides with one or more sialic acid residues. Gangliosides are most abundant in the plama membrane of nerve cells . So far more than 40 different gangliosides have been identified.