Lipids

• What are lipids made of?

  Fatty acids and glycerol

  
• Lipids are energy rich hydrophobic molecules
• Name 3 types of lipids

  1. Fatty acids
  2. Phospholipids
  3. Glycerides
• What type of fat is this?

  Unsaturated fat - double bond

  
• What type of fat is this?

  Saturated fat - no double bond

  
• What does monounsaturated mean?

  One double bond in hydrocarbon chain
• What does polyunsaturated mean?

  Many double bonds in hydrocarbon chain
• How does a triglyceride form?

  Condensation reactions forming an ester bond between the glycerol and fatty acid.
• Triglyceride diagram

  
• What bond forms between a fatty acid tail and glycerol?

  Ester bond
• One molecule of fatty acid

  
• What are 4 features of saturated fat?

  1. No double bonds
  2. Solid at room temperature
  3. Higher melting points
  4. Animal fats
• What are 4 features of unsaturated fats?

  1. Double bonds
  2. Liquid at room temperature
  3. Lower melting points
  4. Plant fats
• Why are lipids an excellent source of energy?

  High numbers of energy storing carbon-hydrogen bonds
• What makes lipids a good storage molecule?

  Low mass to energy ratio
• Lipids have a high ratio of hydrogen to oxygen atoms, when oxidised, lipids produce metabolic water. Why is this useful for camels?


  Camel humps full of lipids that can be metabolised to produce water.
• Lipids are large and non polar, they do not dissolve in water. Why is this an advantage?

  Does not affect osmosis in cells.
• Lipids waterproof plants by being in the waxy cuticle of plants.
• Lipids act as thermal insulators as they are present as a fat layer on animals such as seals.
• Lipids surround organs to protect them from damage.
• Phospholipids have a hydrophilic head and a hydrophobic tail

  
• How are triglycerides and phospholipids different?

  Triglycerides have 3 fatty acid tails phospholipids have 2 fatty acid tails.
• Test for fats

  1. Add Ethanol to solution
  2. THEN add water
  3. Shake
  4. White emulsion = positive test