Presentation is loading. Please wait.

Presentation is loading. Please wait.

Metabolism and Nutrition Definitions: metabolism, catabolism, anabolism Trophic Strategies Essential versus Nonessential Nutrients Two classes of vitamins.

Similar presentations


Presentation on theme: "Metabolism and Nutrition Definitions: metabolism, catabolism, anabolism Trophic Strategies Essential versus Nonessential Nutrients Two classes of vitamins."— Presentation transcript:

1 Metabolism and Nutrition Definitions: metabolism, catabolism, anabolism Trophic Strategies Essential versus Nonessential Nutrients Two classes of vitamins

2 Coupling reactions through common intermediates

3 Different ways the cells utilize the high energy bonds in ATP Coupling endergonic and exergonic reactions Phosphate group transfers Inorganic pyrophosphatase (ATP yields AMP + PPi)

4 High Energy Compounds - Free Energy Currency 1. ATP and phosphoryl group transfer

5 Phosphorylated compounds and regeneration of ATP Substrate level phosphorylation - direct transfer of phosphate catalyzed by kinases Oxidative phosphorylation - indirect ATP generation from proton gradient

6 Thermodynamics versus Kinetics Thermodynamics - Will this reaction happen?  G, K eq, E Kinetics - How fast will it happen? Enzymes

7  G is a state function Only depends on the current state, not the path to get there Addtive - can add the  G of reactions together

8 The standard free-energy changes for the reactions below are given. Phosphocreatine ® creatine + Pi DG'° = –43.0 kJ/mol ATP ® ADP + Pi DG'° = –30.5 kJ/mol What is the overall DG'° for the following reaction? Phosphocreatine + ADP ® creatine + ATP 1. –73.5 kJ/mol 2. –12.5 kJ/mol 3. +12.5 kJ/mol 4. +73.5 kJ/mol 5. DG'° cannot be calculated without Keq'.

9  G =  G 0’ + RTln K  G 0’ = -RTlnK eq Only use at equilbrium, when  G = 0 What is the difference between  G and  G 0’ ?  G - can vary within a reaction depending on reaction conditions. At equilibrium, is 0.  G 0’ - set value of  G at standard state

10 Enzymes! 1. Alter the rate of a reaction 2. Lower the transition state for the forward and reverse reactions 3. Only function in a reaction that would occur without it Spontaneous reactions (negative  G) 4. Are unchanged

11 Mechanisms to Control of Flux 1. Allosteric control 2. Covalent modifications 3. Substrate Cycles 4. Genetic Control

12 Near equilibrium reactions -  G is close to zero -Reactants and products are close to Keq values -Easily reversible -Equilibrium is quickly restored

13 Far equilibrium reactions -Very large negative  G. What does this mean about [products]/[reactants]? -Reactants accumulate -You are limited by your enzyme -Changes in [substrate] have little effect on reaction -Changes in the enzyme may affect

14 Thermodynamics and Metabolism Implications of far from equilibrium 1. Metabolic pathways are irreversible 2. Every metabolic pathway has a first committed step - rate limiting step - large negative  G 3. Catabolic and anabolic pathways differ. 4. For a multistep pathway as a whole, the overall flux is determined by the rate limiting step

15 1) Oxidation - Reduction Reactions 2) Group transfer reactions 3) Eliminations, isomerizations, and rearrangements 4) Making or breaking carbon bonds Know these

16 Glucose Transport Nonmediated versus mediated Different types of transport - carriers vs. channels - passive (facilitated) versus active Uniporters, sympoters, antiporters Tissue specific glucose transport - GLUT1, GLUT2, GLUT4

17 Overview of Glycolysis Stage 1 - prep phase Stage 2 - Energy Recovery Glucose + 2 NAD + + 2 ADP + 2 Pi 2 pyruvate + 2 NADPH + 2ATP + 2 H 2 O+ 4 H +

18 Summary of Preparatory Phase

19 Energy Harvesting Phase

20 Metabolism of Hexoses other than Glucose

21

22 Glycogen Metabolism and Gluconeogenesis


Download ppt "Metabolism and Nutrition Definitions: metabolism, catabolism, anabolism Trophic Strategies Essential versus Nonessential Nutrients Two classes of vitamins."

Similar presentations


Ads by Google