Lipids

• Cholesterol

  A steroid (type of triglyceride)HydrophobicLocated among the hydrocarbon chains of the phospholipid bilayer.

  
• The properties of a phospholipid.

  1. Fatty acid molecules are hydrophobic and are insoluble in water...form hydrophobic tails.2. Phosphate head is hydrophilic and soluble in water.

  
• What is a phospholipid?

  Glycerol joined to 2 fatty acids and a phosphate group.

  
• Function of triglycerides?

  1. Excellent energy store as release more energy per unit mass than carbohydrates.2. Insulation (fats)3. Protective layer (animals)
• Compare fats and oils

  Both Triglycerides.Fats are solid at room temperature and oils are liquids at room temperature.
• What is an unsaturated fatty acid?

  1. The carbon atoms in the hydrocarbon tail have at least one C=C (monounsaturated). If they have more than one C=C they are polyunsaturated.

  
• What is a saturated fatty acid?

  1. The carbon atoms in the hydrocarbon tail are all linked by C-C bonds.2. Every Carbon is bonded to two Hydrogen atoms (carbon is fully bonded/saturated)

  
• What is produced when a triglyceride is hydrolysed?

  1 Glycerol3 Fatty Acids3 Water Molecules
• How does a triglyceride form?

  Condensation reactions occur between the OH groups of the glycerol and the carboxyl group of each of the 3 fatty acids.3 Ester bonds form.

  
• What are fatty acids?

  Organic acidsLong hydrocarbon tails linked to a carboxyl (-COOH) group.There are 70 different types of fatty acid.

  
• Draw a fatty acid

  
• Draw Glycerol

  
• How does a triglyceride form?

  Through condensation reactions between 1 glycerol molecule and 3 fatty acid molecules.

  
• 2 main types of lipids

  1. Triglycerides (fats and oils)2. Phospholipids (in cell membranes), fats and oils.
• Lipid solubility?

  Insoluble in water (hydrophobic)Soluble in Organic Solvents
• Why are lipids macro molecules but not polymers?

  They are made of only 4 sub-units (glycerol and 3 fatty acids)

  
• What elements do lipids contain?


  Carbon, Hydrogen and Oxygen. The ratio of Hydrogen to Oxygen is much greater than 2:1