All Lipids are hydrophobic. That is the one property they have in common. This group of molecules includes fats and oils, waxes, phospholipids, steroids (like cholesterol), and some other related compounds. Lipids contain carbon, hydrogen, and oxygen. Lipids are an important part of living cells. Together with carbohydrates and proteins, lipids are the main constituents of plant and animal cells. Lipids are easily stored in the body. They serve as a source of fuel and are an important constituent of the structure of cells. Another examples of an important lipid is triglycerides.