Question #fb9b0
1 Answer
Energy storage and compartmentalization.
Explanation:
Lipids are long carbon chains that contain a lot of chemical potential energy. Organisms store extra energy in lipid reserves called adipose tissue. More energy is stored per gram of lipid than per gram of protein or carbohydrate.
But lipids are much more than dense energy reserves, they are necessary for cells -- and multicellular life -- to exist at all. You know how oil and water don't mix? Cells take advantage of this by separating themselves from their environment with an oily lipid membrane called a phospholipid bilayer.
On the inside, eukaryotic cells use lipids to subdivide their cytoplasm into organelles for specialized functions. For example, DNA is safely housed away in the nucleus behind a lipid membrane. Mitochondria generate ATP from glucose by pumping H+ ions across their double-membrane. Neurons fire electrical signals by maintaining ion gradients across their lipid membrane. Without lipids, everything in cells would be mixed together into a big disastrous soup!
