lipids+Functions

On function for Lipids is that of **Energy storage**. Lipids contain a lot of calories in a small space. Since Lipids are generally insoluble in polar substances such as water, they are stored in special ways in you body's cells. Lipids can also function as structural components in the cell. Phospholipids are the major building blocks of cell membranes. Lipids are also used as hormones that play roles in regulating our Physiology (metabolism). Most lipids are composed of some sort of fatty acid arrangement. The fatty acids are composed of methylene (or Methyl) groups, and are not water soluble. **Fatty Acids: **The lipid building blocks: The common building block for most of the different types of lipids is the fatty acid. Fatty acids are composed of a chain of methy lene groups with a Carboxyl functional group at one end. The methyl chain is the fatty part, the Carboxyl, the acid. The fatty acid chains are usually between 10 and 20 Carbon atoms long. The fatty "tail" is non-polar (**Hydrophobic**) while the Carboxyl "head" is a little polar (**Hydrophillic**). **Triglycerides** : Energy Storage, Three fatty acids bonded to Glycerol. Triglycerides are Energy-storage molecules. They are formed by connecting three fatty acids (shown in black) to the red part of the molecule on the left, Glycerol. As you can imagine, the three fatty acids together, contain a lot of Energy (aka Calories). Fat has a lot of calories. The flabby stuff most of us have on certain parts of our bodies is cells filled with triglycerides. In trigylcerides, a fatty acid is joined to each of the three Carbons of Glycerol by Dehydration Synthesis to form a molecule which stores a lot of calories in a small space.