Lipids And Cell Membranes
Body cells have a membrane that is quite complicated but it can be represented by a double layer of lipids or lipids attached to proteins. Thus the behavior of lipids and lipid-like molecules becomes very important in understanding how a substance may or may not enter a cell. Many biochemical processes that occur in our bodies are becoming better understood as scientists learn more about the lipid-like layer around cells.
Another insight to be gained by understanding the lipid layer around a cell membrane deals with problems associated with pesticides or other lipid-like molecules that get into places other than those intended. The problems arise because many pesticides are lipid-like and may change the way the cell membrane behaves.
Lipids that are found associated with proteins go by the term lipoproteins. Lipids attached to sugars or carbohydrates are called glycolipids. There are also lipids attached to alcohols and some to phosphoric acids. The attachment with other compounds greatly alters the behavior of a lipid, often making one end of the molecule water soluble. Such new substances are bipolar and can become involved in aqueous chemistry. This is important because it allows lipids to move out of one's intestine and into the blood stream. In the digestion process, lipids are made water soluble by either being broken down into smaller parts or becoming bipolar through association with another substance. The breaking down is usually done via two different processes. One is called hydrolysis, which means chemical reaction with water, and the other is called saponification.