Lipid
Biological lipids are set of compounds that are chemically diverse, but all share an insolubility in water1.
Practical Functions
Fats and oils refer to lipids that function as the primary form of stored energy in the body1.
Phospholipids and sterols serve as cellular structural components1.
Other lipids serve as:
Principles of Cellular Lipid Function
Fatty acids are efficient forms of energy storage for cells since they are water-insoluble hydrocarbons1. Fatty acids are highly reduced (low oxygen-to-hydrogen ratio) allowing them to store large amounts of potential chemical energy1. Triacylglycerols do not need hydration due to their water-insolubility, making these “low maintenance” and efficient1. Storage of hydrophobic fats as triacylglycerols is also highly efficient because water is not needed to hydrate the stored fats.
Membrane lipids consist of hydrophobic tails attached to polar head groups1. A variety of lipids, including glycerophospholipids and sterols compose cellular membranes1.