Every type of lipid contains oxygen, hydrogen and carbon, but a specific type known as a phospholipid also contains phosphate and nitrogen. All of the lipids are considered organic compounds due to the presence of carbon, and they are insoluble in water. The varying structure of lipid molecules results in their different types.
Fatty acids, soaps, detergents, oils, phospholipids, steroids, fat-soluble vitamins and terpenes are the most common kind of lipids. Fatty acids are long chains that are created by the process of hydrolysis. The unique structure of a fatty acid gives it a distinct melting point.
Lipids are able to store energy for a cell, signal cellular responses and provide structure to the membranes of the cell.