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Published byJean Montgomery Modified over 9 years ago
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Transit and Metabolic Maps: Complex and Functional
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Glycolysis Coupled with Cellular Respiration Maximizes Energy Generation
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Carbon Oxidation is Coupled with Energy Rich Reduction Which molecule is more energy rich on a per carbon basis?
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Free- Energy Universal-Currency: ATP ATP hydrolysis is exergonic ATP + H 2 O ADP + P i ∆ G° ʹ = - 30 kJ/mol ATP hydrolysis drives metabolism in heterotrophs Light energy is trapped as ATP in phototrophs Why is ATP an excellent energy currency?
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ATP: High Phosphoryl-Transfer Potential ATP and hydrolysis products differences: Electrostatic repulsion Resonance stabilization Hydration stabilization How can an energetically unfavorable reaction be made spontaneous?
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Substrate-Level ATP Phosphoryation Requires High Phosphoryl-Transfer Potential Standard Free Energy of Hydrolysis
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Duration of Alternative Energy Sources Anaerobic Systems Aerobic Systems ATP: tennis serve Oxidative phosphorylation: Creatine phosphate: sprint race > 500 m Glycolysis: 200 m dash
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ATP: A Multifunctional Metabolite High turnover (ca. 90 lbs/24 hrs)
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Additional Activated Carriers Nicotinamide Adenine Dinucleotide (NAD + ) Electron carriers in oxidation-reduction reactions NADH functions in catabolism NADPH functions in anabolism Nicotinamide Adenine Dinucleotide Phosphate (NADP + )
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Additional Activated Carriers Flavin adenine dinucleotide (FAD) Electron carriers in oxidation-reduction reactions FADH functions in both catabolism and anabolism
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Substrate Specificity for Dinucleotide Oxidation-Reduction Reactions
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What is the reducing agent for this reaction? Fatty Acid Biosynthesis via Keto Reduction to a Methylene Unit
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Coenzyme A: an Activated Carrier of Two Carbon Fragments Coenzyme A structure Acetyl CoA + H 2 O ↔ Acetate + CoA + H + ∆ G° ʹ = -31 kJ/mol
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Activated Carries Utilized in Metabolism
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Coenzymes Derived from Vitamins What coenzymes are derived from these vitamins?
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Metabolic Regulation Substrate accessibility (compartmentalization) Enzyme amount (transcriptional and translation control) Catalytic activity (allosteric control, covalent modifications, hormone signaling, and cell energy status) Energy charge = [ATP] + ½[ADP]/([ATP] + [ADP] + [AMP])
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Energy Utilization Linked with Building and Degrading Metabolites What macromolecules are stored and/or metabolized by humans for energy?
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Metabolic Fuel Generation by Digestion Match the enzyme with the reaction: - Protease - Amylase - Lipase
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Lipid Transport via Lipoproteins (aka Chylomicrons) to Adipocytes Lipoproteins - esterified cholesterol, proteins and triacylglycerols combined Adipose cells
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A Liver Cell Fat globule Mitochondria Glycogen granules Glycogen molecule with sugar units What advantages are there in having glycogen be a branched polymer? Human Sugar Storage in Liver and Muscle Tissue
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Glycogen Degradation by Glycogen Phosphorylase (Phosphorolysiss) Trapped in the cell
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Protein Degradation by Ubiquitin Tagging and Proteasome Digestion Cutaway view showing inner chamber Protease active sites
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Proteasome Protein Degradation Protein turnover important in: Cell signaling Maintaining high protein quality
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Does this phosphoarginine metabolite rich in the muscles of certain invertebrates have a high phosphoryl-transfer potential? What function might this metabolite have? Test Your Knowledge…
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∆G of ATP Hydrolysis with Varying [Mg 2+ ] How does decreasing [Mg +2 ] affect ∆ G of ATP hydrolysis? Can this trend be justified?
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Problems: 26, 27 and 41
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