Lipid

A lipid, along with carbohydrate, protein, and nucleic acid, is one of the four classes that all organic compounds can be divided into. Lipids are comprised of glycerol and fatty acids. The glycerol acts as a head with one or more fatty acids attaching to it to create tail like structures. Lipids include fats, oils, and waxes. Lipids with three fatty acids are refereed to as triglycerides.

Lipids can not, or can only partially, dissolve in water. For each fatty acid that attaches itself to the glycerol one water molecule is removed in a process called dehydration synthesis. For each fatty acid that detaches itself one water molecule is needed in a process called hydration.