Lipids are a large group of biological molecules that include phospholipids, fats, oils, waxes and some steroids. Almost all lipids are hydrophobic (i.e. insoluble in water). Lipids play many important different functions in a cell. Lipids are vital component of all cellular membranes. They store energy in the form of fats in the body. Waxy coverings on some leaves are composed of lipids. Lipids are also essential for heat insulation, cellular communication and protection.
