How Are Phospholipids Formed?

A Type of Lipid

• A phospholipid is a specific breed of lipid. Some lipids -- including phospholipids -- serve as structural components, while others act as signaling devices or work to store energy. Phospholipids form the basis of the cell membrane, serving as a barrier between the inside of the cell and the external areas surrounding it.

Phospholipid Functions

• Other than serving as a barrier, phospholipids allow membranes to exhibit several characteristics. They allow cells to alter in size, as well as change shape easily, much like how a balloon filled with water can take shapes. It allows diffusion of certain molecules, including carbon dioxide and oxygen, but prevents others, such as water or glucose from permeating. Phospholipids are also responsible for homeostasis within cells.

Structure

• Phospholipids contain a polar phosphate group, which is one of the reasons why it interacts with water. The bilayer -- which makes up the cell membrane -- forms spontaneously in the presence of water. The "head" of the phosphate group will arrange itself in a manner that points it toward water. The tails of the phospholipids are known as "fatty acids." These tails arrange themselves away from the water.

Discovery and Practical Applications

• The discovery of phospholipids dates to the middle of the 19th century. In 1847, Theodore Nicolas Gobley identified "lecithin" within the yolk of an egg.

  Now, outside of the body, phospholipids can serve other practical purposes. These include extraction and use in foods, such as bread. Their addition allows non-polar items -- such as oils -- to become water soluble.