The main constituents of the plasma membrane are phospholipids, proteins and carbohydrates.
The phospholipds, amphipathic molecules, are regularly organized in the
membrane according to their polarity: two layers of phospholipids form
the lipid bilayer with the polar part of the phospholipids pointing to
the exterior of the layer and the non-polar phospholipid chains in the
interior. Proteins can be found embedded in the lipid bilayer and there
are also some carbohydrates bound to proteins and to phospholipids in the outer face of the membrane.
