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Foodstuffs and their energy contents © Michael Palmer 2014.

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Presentation on theme: "Foodstuffs and their energy contents © Michael Palmer 2014."— Presentation transcript:

1 Foodstuffs and their energy contents © Michael Palmer 2014

2 Carbon pools in carbohydrate and fat metabolism © Michael Palmer 2014

3 Triacylglycerol and its cleavage products © Michael Palmer 2014

4 Solubilization of fat by detergents © Michael Palmer 2014

5 Uptake and re-packaging of digested fat in the small intestine © Michael Palmer 2014

6 The lymphatics drain excess fluid from the interstitial space © Michael Palmer 2014

7 Chylomicrons are drained from the intestine through the lymphatics, bypassing the liver © Michael Palmer 2014

8 Lipoprotein lipase extracts triacylglycerol from chylomicrons © Michael Palmer 2014

9 Two activated forms of fatty acids © Michael Palmer 2014

10 Activation of fatty acids and transport to the mitochondrion © Michael Palmer 2014

11 Reactions in β-oxidation © Michael Palmer 2014

12 Shared reaction patterns in β-oxidation and TCA cycle © Michael Palmer 2014

13 The reaction mechanism of thiolase © Michael Palmer 2014

14 Utilization of propionate © Michael Palmer 2014

15 Organ relationships in triacylglycerol utilization © Michael Palmer 2014

16 Brown fat tissue © Michael Palmer 2014

17 Medium-chain fatty acids ● contain less than 12 carbon atoms ● low content in most foods, but relatively high (10–15%) in palm seed and coconut oil, from which they are industrially prepared ● triglycerides with medium chains are more soluble and more rapidly hydrolyzed by gastric and pancreatic lipase ● not efficiently re-esterified inside intestinal cells; systemic uptake mostly as free fatty acids ● reach mitochondria by diffusion, without prior activation to acyl-CoA and acyl-carnitine

18 Ketone body metabolism © Michael Palmer 2014

19 Synthesis of acetoacetate and β-hydroxybutyrate © Michael Palmer 2014

20 Decarboxylation of acetoacetate © Michael Palmer 2014

21 Acetone can serve as a precursor for gluconeogenesis © Michael Palmer 2014

22 Anticonvulsant effects of acetone and acetol © Michael Palmer 2014

23 The acetyl-CoA carboxylase reaction © Michael Palmer 2014

24 The structure of fatty acid synthase © Michael Palmer 2014

25 Phosphopantetheine acts as a flexible tether in acyl carrier protein © Michael Palmer 2014

26 Fatty acid synthase reactions (1) © Michael Palmer 2014

27 Fatty acid synthase reactions (2) © Michael Palmer 2014

28 Mitochondrial export of acetyl-CoA via citrate © Michael Palmer 2014

29 Mitochondrial export of acetyl-CoA via acetoacetate © Michael Palmer 2014

30 Elongation and desaturation of fatty acids ● elongases reside in mitochondria and endoplasmic reticulum ● chemistry of elongation similar to β-oxidation in mitochondria, similar to fatty acid synthase in the ER ● desaturases occur in the ER, introduce double bonds at various positions ● double bonds are created at least 9 carbons away from the ω end—ω-3 fatty acids cannot be formed and are therefore essential

31 Cerulenin, an antibiotic that irreversibly inhibits fatty acid synthase © Michael Palmer 2014

32 Fatty acid synthase inhibition slows tumor growth in mouse experiments © Michael Palmer 2014

33 The glyoxylate cycle © Michael Palmer 2014

34 Reactions in the glyoxylate cycle © Michael Palmer 2014


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