Lipids

• Lipids are ...

  1. non polar
  2. insoluble in water
  3. dissolve in organic solvents
• Triglycerides are formed of ...

  glycerol and fatty acids
• To form an ester bond a ... reaction must occur.

  condensation
• Unsaturated fatty acids are ...

  1. Do not contain the maximum number of hydrogen atoms
  2. They contain one or more carbon double bonds
  3. They have a kink in their carbon chain
• Saturated fatty acids are ...

  1. They have the maximum number of hydrogen atoms
  2. They do not contain a carbon double bond
  3. They have a straight chain
• A high intake of saturated fats causes ...

  1. A raise in the LDL level
  2. This increases the incidence of atheromas in coronary arteries
  3. Which can lead to angina and heart attack
• A greater intake of unsaturated fats causes ...

  1. A higher level of HDL
  2. HDL's carry excess cholesterol into the liver
  3. It is then eliminated from the body
• What are lipids called when a phosphate group is present?

  phospholipids
• In a phospholipid ...

  1. The phosphate head is hydrophilic
  2. The fatty acid tails are hydrophobic
• Properties of waxes ...

  1. Waterproofing insects exoskeletons
  2. Form the waxy cuticles on plants
  3. They melt above 45 degrees
• Roles of phospholipids ...

  1. Form biological membranes
  2. Electrical insulation - form the myelin sheath which surrounds the axon of nerve cells
• Roles of triglycerides ...

  1. Thermal insulation
  2. Energy reserves in plants as oils - they contain more carbon hydrogen bonds than carbohydrates
  3. Protection against mechanical damage
  4. Metabolic source of water