Lipids

• How do lipids differ from proteins and carbohydrates?


  Lipids are not polymers, while proteins and carbohydrates are.
• What elements do lipids contain?


  Lipids contain hydrogen, carbon, and oxygen.
• What are some functions of lipids?

  Lipids provide energy, insulation, waterproofing, and serve as hormone precursors.
• What is the structure of triglycerides?


  • Consists of one glycerol molecule
  • Contains three fatty acids
  • Joined by ester bonds in condensation
• What type of bond is formed between glycerol and fatty acids in triglycerides?


  An ester bond is formed between the hydroxyl group of glycerol and the carboxyl group of fatty acids.
• What is released as a side product during the formation of triglycerides?

  Three water molecules (3H₂O) are released.
• What is hydrogenation in the context of fatty acids?

  Hydrogenation refers to the process of saturating fatty acid chains.
• How do unsaturated carbon-carbon double bonds affect lipids?

  They make lipids more unsaturated, causing a decrease in melting point.
• What is the state of saturated lipids at room temperature?

  Saturated lipids are solid at room temperature.
• Where are saturated lipids commonly found?

  Saturated lipids are found in animal fat.
• What are the functions and properties of triglycerides?


  • Used as an energy store
  • Source of energy when fatty acid chains are broken down
  • High energy storage due to C-H bonds
  • Hydrophobic fatty acids help in storage
  • Increase water when oxidized, beneficial in dry areas
• What are the components of phospholipids?


  Phospholipids consist of a glycerol molecule, a phosphate group, and two fatty acid chains.
• What is the nature of the phosphate group in phospholipids?


  The phosphate group is hydrophilic and polar.
• How do phospholipids contribute to cell membranes?


  Phospholipids attract water and form bilayers, making up cell membranes.
• What characterizes saturated fatty acids?


  Saturated fatty acids have no carbon-carbon double bonds.
• What characterizes unsaturated fatty acids?


  Unsaturated fatty acids contain double bonds and omit a hydrogen atom from a bond.
• What is the procedure for testing lipids in a sample?


  1. Add 2 cm³ of sample and 5 cm³ of absolute alcohol to a grease-free flat tube.
  2. Shake in water.
  3. Add 5 cm³ of water and repeat with water as control.
• What type of compounds are lipids classified as?

  Lipids are classified as organic compounds.
• What is the significance of the hydrophobic nature of fatty acids in triglycerides?


  The hydrophobic nature helps in the storage of triglycerides by keeping water molecules apart.
• Why do triglycerides release a high amount of energy?


  They have many C-H bonds, which are low energy bonds that release energy when broken down.