Medicine & USMLE


  1. Fatty Acids
  2. Triacylglycerols
  3. Phospholipids
  4. Sphingolipids
  5. Terpenes
  6. Steroids
  7. Waxes


Triacylglycerols, also known as triglycerides or TAGs for short, are lipids that contain a glycerol backbone connected to three fatty acid tails. These fatty acid tails are connected by way of ester linkages. The function of triacylglycerols is to store energy for the body in adipose tissue. Because of their long non-polar fatty acid tails, triacylglycerol is a hydrophobic, or nonpolar, molecule. 

Key Points

  • Fats/Triacylglycerols
    • Also called triglycerides or fats
    • Structure
      • Backbone: Glycerol
      • Attachments: 3 Fatty Acids
        • Attached via ester linkages
    • Roles
      • Stores energy
        • Stored primarily in adipocytes
    • Nonpolar/hydrophobic