Lipids

Lipids are comprised of fats and oils and contain the following elements: Carbon (C), Hydrogen (H) and Oxygen (O)

• Structure: A lipid is comprised of triglycerides or phospholipids.
  Triglycerides consist of one molecule of glycerol linked to three fatty acid molecules. For phospholipids, one fatty acid is replaced by a phosphate
  • Fats: are solid at room temperature (RT)
  • Oils:  liquids at RT - contain different types of fatty acids than fats

Role of lipids in living organisms

• Cell structure
  • Phospholipids & lipoproteins are components of cell membranes
  • Provide heat insulation
  • Stored in the body as adipose tissue under skin (important in aquatic animals such as whales and seals
  • Protect organs e.g. kidney, heart.
  • Waterproofing e.g. oil on human skin (sebum) and birds’ feathers, the cuticles on leaves, seeds and fruits.
  • Found as myelin on some nerves – increases speed at which messages are carried.
• Metabolism:
  • Reserve energy source – has twice the energy value of carbohydrates.