lipid (thing)

Lipids

• Hydrophobic
• Energy storage and structural purposes
• Some play an important role as messengers

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