LIPIDS

• Lipids


  -type of biological molecule which often we think of as oils/fats,

  -made by the liver, also from diet

  -hydrophobic, therefore must be carried by lipoproteins
• Uses of lipids

  -makes hormones

  -gametes made from cholesterol

  -energy storage

  -insulation

  -cell membrane

  -waterproofing
• What is a negative of cholesterol

  Excess cholesterol in blood linked to heart disease
• FATTY ACID & GLYCEROL

  
• FATTY ACID + GLYCEROL

  
• Triglycerides

  3 fatty acids and 1 glycerol, each fatty acid forms ester bond with glycerol in condensation reaction produced by hydrolysis.
• Where do differences in the properties of fats and oils come from?


  Variations in the fatty acids (saturated, monounsaturated, polyunsaturated)
• Phospholipids


  Hydrophilic phosphate head with a hydrophobic fatty acid tail
• Test for lipids


  -Take a dry grease free test tube

  -To 2cm3 of sample add 5cm3 ethanol

  -Shake tube thoroughly to dissolve any lipid in the sample

  -Add 5cm3 of water and shake gently

  -Milky-white colour shows a positive result for lipid (emulsion)

  -As a control repeat process using water instead of sample and solution should remain clear