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.
Oilseed rape
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