Plasma Membrane

 Chemical composition of the plasma membrane:

Lipid bilayer: forms the basic fabric of the membrane, constructed of phospholipids. (Polar head of the phospholipid is hydrophilic and nonpolar tail that is hydrophobic) 

Glycolipids: phospholipids with attached sugar groups, combined with cholesterol stabilizes the membrane and restrains movement of the phospholipids. 

Lipid rafts: dynamic assemblies of saturated phospholipids, more stable and orderly and less fluid, and can include or exclude specific proteins to various extents. Assumed to be concentrating platforms for molecules needed for cell signaling

Integral  proteins: firmly inserted into the lipid bilayer, transmembrane proteins that span the entire width of the membrane, have hydrophobic and hydrophilic regions allowing them to interact with the non-polar lipid tails and the water inside and outside the call. Mainly involved in transport, form channels and some act as carriers that bind to a substance to move it across the membrane. 

Peripheral proteins: not embedded in the lipid, they attach loosely to integral proteins and are easily removed without disruption. They help support the membrane from its cytoplasmic side, some proteins are enzymes and others are involved in mechanical functions such as changing cell shape during cell division and muscle cell contraction.