Fats and Oils: Energy in storage

  • Vertebrates store excess glycogen as fats
  • Some plants store food energy as oils
  • Fats and oils contain more energy-rich carbon-hydrogen bonds than carbohydrates and therefore contain more chemical energy.
  • Because fats are nonpolar, they aren't "weighted down" by water molecules like glycogen, allowing them to store six times as much energy as glycogen.
  • A fat molecule consists of three molecules of fatty acid joined to one three-carbon alcohol with three hydroxyl groups.
    • A fatty acid consists of a long hydrocarbon chain that terminates in a carboxyl group (-COOH).
    • Carboxyl group gives one end of the chain acidic properties.
    • Fat molecules are completely nonpolar and hydrophobic