L17 – Energy Release from Fat
Slide 3 – Biological functions of lipids
• Components of cell membranes (phospholipids and cholesterol)
• Precursors of hormones
- Cholesterol --> steroid hormones
- Arachidonic acid --> prostaglandins
• Long term fuels (triglycerides)
Indicate the importance of triglyceride fat for long term fuel storage
Slide 4 – Efficiency of Triglycerides as Fuel
• Compact storage: triglycerides stored as large fat droplets in fat cells of adipose tissue
• Large body stores
- 70kg adult has 11kg fat (as triglycerides), 120g glycogen in liver, 10g glucose
• Efficiency on weight basis:
- 1g fat yields 38kJ
- 1g protein yields 21kJ
- 1g carbohydrate yields 17kJ
Slide 5 – Structure of triglyceride fat (triacylglycerols)
• Palmitic acid: 16 carbons, 0 double bonds
Describe the role of adipose tissue lipase in the breakdown of triglycerides into fatty
acids and glycerol
Slide 6 – Breakdown of stored triglyceride fat in adipose tissue
• Have to start breaking down triacylglycerol to break down fat
• Adrenaline (when you exercise), glucagon when (blood glucose is low)
, • Fatty acids hydrophobic, can’t easily travel in blood
- Has specialised transport system (albumin), taken to other tissues that use the energy
Slide 7 – Metabolism of glycerol
• Glycerol is water-soluble and is taken up by all tissues
Describe how fatty acids are activated to their CoA esters, and how they are transported
into mitochondria via the carnitine shuttle system
Slide 9 – Activation of long chain fatty acids
• Fatty acyl-CoA: stores energy in the thioester bond
• Takes place in the cytosol
Slide 3 – Biological functions of lipids
• Components of cell membranes (phospholipids and cholesterol)
• Precursors of hormones
- Cholesterol --> steroid hormones
- Arachidonic acid --> prostaglandins
• Long term fuels (triglycerides)
Indicate the importance of triglyceride fat for long term fuel storage
Slide 4 – Efficiency of Triglycerides as Fuel
• Compact storage: triglycerides stored as large fat droplets in fat cells of adipose tissue
• Large body stores
- 70kg adult has 11kg fat (as triglycerides), 120g glycogen in liver, 10g glucose
• Efficiency on weight basis:
- 1g fat yields 38kJ
- 1g protein yields 21kJ
- 1g carbohydrate yields 17kJ
Slide 5 – Structure of triglyceride fat (triacylglycerols)
• Palmitic acid: 16 carbons, 0 double bonds
Describe the role of adipose tissue lipase in the breakdown of triglycerides into fatty
acids and glycerol
Slide 6 – Breakdown of stored triglyceride fat in adipose tissue
• Have to start breaking down triacylglycerol to break down fat
• Adrenaline (when you exercise), glucagon when (blood glucose is low)
, • Fatty acids hydrophobic, can’t easily travel in blood
- Has specialised transport system (albumin), taken to other tissues that use the energy
Slide 7 – Metabolism of glycerol
• Glycerol is water-soluble and is taken up by all tissues
Describe how fatty acids are activated to their CoA esters, and how they are transported
into mitochondria via the carnitine shuttle system
Slide 9 – Activation of long chain fatty acids
• Fatty acyl-CoA: stores energy in the thioester bond
• Takes place in the cytosol
