Answer: Lipids are essential to your health because they support a
number of your body’s functions. Lipids enable the fat-soluble vitamins A, D, E,
and K to be absorbed from food and regulate cholesterol metabolism. Lipids are
made up of several fatty acids (containing long chains of carbon and hydrogen
atoms), bonded to a glycerol. They are typically triglycerides, which have
three fatty acids attached to one glycerol.
Lipids have the highest caloric value of any nutrient. One
gram of lipids provides 9.3 k. cal. of energy. Lipids are insoluble in water. They
are stored in your body as reserve food, which you can use when you need it. Lipids
form an insulating layer that helps maintain body temperature. The myelin
sheaths around your nerves contain lipids that prevents the passage of nerve
impulses to adjacent nerve fibers. Lipids are also structural components of your
cells, and their presence is required for certain enzymes and hormones.
Answer: all cells in your body have whats called a phosphoLIPID bilayer that acts as a gated wall between the outside world and the cells internal workings. this is where a lot of lipids get used. Other than that there are fat pads over the kidneys and underneath eyebrows, and the layer underneath the skin that acts as an insulator.
Answer: Lipid: Fat-soluble," an operational term describing a solubility characteristic, not a chemical substance, i.e., denoting substances extracted from animal or vegetable cells by nonpolar solvents; included in the heterogeneous collection of materials thus extractable are fatty acids, glycerides and glyceryl ethers, phospholipids, sphingolipids, long-chain alcohols and waxes, terpenes, steroids, and "fat-soluble" vitamins such as A, D, and E.
This information was taken from www.webmd.com
To find out what lipids do please see this website: http://bioweb.wku.edu/courses/biol115/Wyatt/Biochem/Lipid/lipid1.htm