Lipids are nonpolar molecules that include fats, oils, and cholesterol. Most lipids contain chains of carbon atoms bonded together, these are called fatty acids.
Fats and oils are two familiar types of lipids.
Lipids have several different functions. They can be broken down and used as a source of energy. They also make up cell membranes, and can be used to make hormones.
In fats and oils you will find two types of fatty acids, saturated and unsaturated. Saturated fats contain fatty acids with only single carbon-carbon bonds. Unsaturated fats have at least one carbon-carbon double bond (shown with a double line in the image on the right).
Read more about Lipids.