Introduction to Lipid Biochemistry

• What is the significance of unsaturation in fatty acids?

  It affects the properties of fatty acids
• What are the main classes of lipids mentioned?

  Fatty acids, triacylglycerols, phospholipids, sterols
• How do lipids interact with water?

  They are hydrophobic or amphipathic
• What are triacylglycerols composed of?

  Esters of free fatty acids with glycerol
• What are wax esters made from?

  Esters of free fatty acids with long-chain alcohols
• What is the role of phospholipids in cells?

  Key components of cell membranes
• What are sphingolipids classified as?

  Complex lipids
• What are the sources of lipids?

  Exogenous and endogenous sources
• What is the principal body region for triglycerides?

  White adipose tissue
• Why is triacylglycerol a good energy source?

  It provides high energy yield during metabolism
• How many ATP molecules are gained from glucose?

  Approximately 32 ATP molecules
• What is the first step in lipolysis?

  Hydrolysis of triacylglycerols
• Where does fatty acid oxidation primarily occur?

  In the mitochondria
• What is the role of acyl CoA synthetase?

  Activates fatty acids to their CoA derivative
• How does fatty acid synthesis differ from oxidation?

  Synthesis occurs in the cytosol, oxidation in mitochondria
• What is the effect of unsaturation on membrane fluidity?

  It increases membrane fluidity
• What is the source of endogenous unsaturated fatty acids?

  Fatty acid desaturase enzyme
• What is the role of cholesterol in cell membranes?

  Maintains membrane integrity
• What enzyme is targeted by statins?

  HMG-CoA reductase
• How are cholesterol esters formed?

  By esterification of cholesterol to fatty acids
• What is the function of lipoproteins?

  Transport lipids in the circulation
• What are chylomicrons?

  Transport vehicles for dietary lipids
• What happens to esterified lipids in tissues?

  Released as free fatty acids by lipoprotein lipase
• What are the key points about triacylglycerols and phospholipids?

  • Triacylglycerols are major energy storage compounds
  • Highly reduced chemicals with high energy electrons
  • Phospholipids are amphipathic and essential for cell membranes
  • Work with cholesterol for membrane integrity and fluidity
  • Unsaturation in fatty acids maintains membrane fluidity
  • Sterols and triacylglycerols are transported in lipoproteins