AS AQA Biology: Biochemistry: Lipids

Biochemistry

Lipids

Mixed group of hydrophobic compounds made of Carbon, Hydrogen and Oxygen. Functions include: insulation, energy storage, protection, waterproofing, cell membrane, production of hormones.

Triglycerides

Glycerol and fatty acids combine via condensation to create triglycerides. R group of a fatty acid can be saturated or unsaturated. In phospholipids there are only two fatty acid chains, rather than three, and this is substituted by a phosphate group.

If there are no C=C double bonds in the hydrocarbon chain, then it is a saturated fatty acid (i.e. saturated with hydrogen). These fatty acids form straight chains, and have a high melting point. GOOD

If there are C=C double bonds in the hydrocarbon chain, then it is an unsaturated fatty acid (i.e. unsaturated with hydrogen). These fatty acids form bent chains, and have a low melting point. Fatty acids with more than one double bond are called poly-unsaturated fatty acids (PUFAs). BAD

This is a condensation reaction; the new bonds are called ester bonds.

Triglycerides are insoluble in water. They are used for storage,…