The Cell membrane Essays - Nutrition, Membrane Biology, Lipids

The cell membrane is made up of a phospholipid bilayer. The outer layer is composed of hydrophilic phospholipid heads which are water loving molecules. The inside layer is made of hydrophobic fatty acid tails that repel water so therefore the plasma membrane or cell membranes is capable of self assembly. The fatty acids can either be saturated and unsaturated. Saturated fatty acids have no carbon-carbon double bonds while the unsaturated fatty acids have one to four double bonds between adjacent carbon atoms. Cholesterol, an important building block in the plasma membrane, is transported through the bloodstream in the form of lipoproteins. In animal cells cholesterol prevents packing of fatty acids and thus lowers the requirement of unsaturated fatty acids. This maintains the fluid nature of the cell membrane without it becoming too liquid at body temperature. Proteins which are the building blocks for lipoproteins are directly inserted into the phospholipid bilayer. They are called protein receptors and serve in helping the cell communicate with other cells. This is a basic explanation of how the cell membrane is composed.