Roles of lipids

• What is one role of lipids in the cell membrane?

  They contribute to membrane flexibility
• How do lipids contribute to the transfer of substances across membranes?

  They facilitate lipid-soluble substance transfer
• How much energy do lipids provide when oxidized compared to carbohydrates?

  More than twice the energy
• Why are lipids useful for waterproofing?

  They are insoluble in water
• What valuable substance is released when lipids are oxidized?

  Water
• What do plants and insects have that conserves water?

  A waxy, lipid cuticle
• What do mammals produce from sebaceous glands in the skin?

  An oily secretion
• How do fats help with insulation?

  They are slow conductors of heat
• Where are fats stored to help retain body heat?

  Beneath the body surface
• What role do fats play in nerve cells?

  They act as electrical insulators
• What is fat often stored around?

  Delicate organs
• At what temperature are fats solid?

  10-20°C
• What state are oils at room temperature?

  Liquids
• What are the main functions of lipids in biological systems?

  • Contribute to cell membrane flexibility
  • Provide energy when oxidized
  • Serve as waterproofing agents
  • Provide insulation
  • Offer protection to organs