Lipids

Lipids contain the elements Carbon, Hydrogen and Oxygen

Triglycerides are the main types of lipids and are usually known as fats and oils.

Triglycerides are formed by the combination of three fatty acid molecules and one molecule of Glycerol.

This is a condensation reaction and for every trigyceride formed, three molecules of water are released.

Triglycerides are insoluble in water but soluble in organic solvents such as alcohol. This is because of the long Hydrogen tails of the fatty acids.

Triglycerides are HYDROPHOBIC.

Roles of lipids

Lipids are an energy source- when oxidised, lipids provide more than twice the energy as the same mass of carbohydrates.

Waterproofing - lipids are insoluble in water and therefore useful as waterproofing.

Insulation - fats are slow conductors of heat and when stored beneath the body surface, they help retain heat.

Protectection - Fat is often stored around delicate organs such as the kidneys.