04-Carb and Lipid Metabolism slides.pdf - Carbohydrate and Lipid Metabolism M.J VandeHaar meal Protein Lactose meal How does this stuff work Time Fiber

04-Carb and Lipid Metabolism slides.pdf - Carbohydrate and...

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9/29/17 1 Carbohydrate and Lipid Metabolism M.J. VandeHaar How does this stuff work? Protein Lactose Starch Work Fiber Lactose Time meal meal Interaction of carbohydrate and lipid metabolism absorbed CHO propionate AA glycerol glucose milk lactose CO 2 and H 2 O gluconeogenesis lactate glycogen incomplete oxidation complete oxidation absorbed lipid acetate fatty acid CO 2 and H 2 O lipogenesis ketones incomplete oxidation complete oxidation Store as triglyceride milk fat Glucose can be converted to fatty acids but fatty acids cannot be converted to glucose!
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9/29/17 2 Terminology in Metabolism TERMINOLOGY "gluco" - glucose "lysis" dissolution, breakdown "glyco" - sugar "genesis" creation, synthesis "lipo" - lipid "keto" - ketone "hyper" - high "hypo - low "neo" new "emia" presence of a substance in blood Pattern of nutrient absorption within a day Rate of nutrient absorption Time meal meal As compounds are absorbed into blood, they are removed by tissues and some are stored for later release to avoid wild fluctuations in their blood concentrations. High concentrations of a metabolite like glucose result in urinary losses.
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9/29/17 3 Glucose metabolism Do these reactions all happen in same cell? Do they all happen at the same time? Carbohydrate Metabolism: Glycolysis A. Glycolysis (Glucose breakdown) 1. Overall reaction : 1 ATP 1 ATP 2 NAD 2 NADH 2 NAD glucose glucose-6-phosphate →→→→→→→→ 2 pyruvate 2 lactate 4 ATP 2.Anaerobic glycolysis→→lactate + 2 ATP b.When and where? c.What happens to products?
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9/29/17 4 Carbohydrate Metabolism: Aerobic glycolysis Aerobic glycolysis - pyruvate + 6 ATP a. Purpose: quick energy b. When and where? Most cells when the electron transport chain or other reactions are able to use up the NADH, so activity is directly related to activity of the cell and availablity of glucose vs. other fuels. muscle: related to work level and rate of protein synthesis brain: always occuring adipose tissue: related to rate of fat synthesis Carbohydrate Metabolism: HMP pathway Pentose phosphate pathway (hexose monophosphate pathway, HMP; Fig. 7.3 of text) 1. Net reactions: G-6-P →→ CO 2 + H 2 O + 12 NADPH or G-6-P →→ triose phosphates, ribose 2. Purpose: Generates other sugars, such as ribose for RNA and DNA synthesis. Generates NADPH (reducing equivalents) for use in reducing reactions, such as fatty acid biosynthesis . 3. When and where? cytosol, especially in tissues in which fatty acid synthesis is active controlled by the ratio of NADP to NADPH, so high after a meal that has plenty of starch, sugar, or glucogenic compounds
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9/29/17 5 Carbohydrate Metabolism: TCA cycle C. TCA Cycle (tricarboxylic acid cycle, Krebs cycle, citric acid cycle) 1. Net reaction:
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