Explain lipids?

Lipids: Lipids function as energy-storing molecules such as fats and oils, protective waxes, digestive tract lubricants, heat insulation such as whale blubber, and electrical insulation around nerve fibers. Lipids make up most of the material that forms cell membranes. Lipids are not water soluble - that is, they are insoluble - because the hydrocarbon ends (tails) of the molecules are nonpolar (hydrophobic, from the Greek meaning water fearing) and gather towards the center of a fat globule suspended in water. The polar (hydrophilic, or water loving) ends of the lipid molecules seek out and interact with the water molecules. Lipids are composed mainly of carbon, hydrogen, and oxygen. Some types also contain phosphorus and nitrogen.