Lipid

• Phospholipids are a type of lipid that make up the cell membrane and have a hydrophilic head and hydrophobic tail.
• • Triglyceride/fatty acid in lipid can be broken down and enter Krebs cycle to yield ATP
  • Lipids have high H:O ratio readily oxidized
  • Phospholipid moiety of membrane facilitates transport of lipid soluble substances
• Lipid for waterproof layer in cuticle of plants and oil on skin of mammals
• Adipose tissue as shock absorber which protects internal organ from mechanical damage
• Lipid is a solvent for fat soluble vitamins
• Myelin sheath around nerve fibre enhances transmission of nerve impulse
• Cholesterol is an important component of animal cells, especially plasma membranes
• Heat insulator conserves body heat in warm-blooded animals
• Energy store - lipids are the most concentrated source of energy per unit weight.
• Cholesterol controls the fluidity of phospholipid bilayer of cell membrane