Chpt_3_metabolism

Chpt_3_metabolism - Chapter 3 Cell Metabolism This will...

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Unformatted text preview: Chapter 3 Cell Metabolism This will probably be your most difficult chapter Chapter Outline • Types of Metabolic Reactions • Metabolic Reactions and Energy • Reaction Rates Metabolism – Metabolism = sum of all chemical reactions occurring in a cell – Energy metabolism = reactions involved in energy storage and use I. Types of Metabolic Reactions • Chemical Reactions • Hydrolysis and Condensation • Phosphorylation and Dephosphorylation • Oxidation-Reduction Chemical Reactions – Reactants (or substrates) Products A + B C + D – Direction of reaction • Forward • Reverse Metabolic Reactions – Catabolism = breakdown of organic molecules – Anabolism = synthesis of organic molecules Metabolic Pathways Sequence of enzymatic reactions that begins with initial substrate, progresses through intermediates and end with a final product. Oxidation-Reduction Reactions: OIL RIG II. Metabolic Reactions and Energy • Energy-releasing and Energy-requiring Reactions • Energy Changes in Reactions • Activation Energy Energy Capacity to do work Energy-Releasing and Energy-Requiring Reactions – Catabolic reactions • Release energy – Anabolic reactions • Require energy First Law of Thermodynamics – Human body is an open system – Energy can be neither created nor destroyed – Energy Changes in Reactions – Energy exchanged in all reactions – Molecules possess energy – Change in energy of a reaction = E – W E = E products – E reactants – Energy-releasing Reaction – Energy in reactants > Energy in products – Energy Released Energy Change in Energy-releasing Reaction Energy-requiring Reaction – Energy in reactants < Energy in products – Energy input required Energy Change in Energy-requiring Reaction Types of Energy – Kinetic energy – – Potential energy – • Chemical energy – Potential and Kinetic Energy Direction of Reactions – Energy releasing reactions • G E is NEGATIVE • Occurs • • Energy-requiring reactions • G E is POSITIVE • Does • Requires • Coupling Reactions Energy from energy-releasing reaction used to drive energy-requiring reaction Equilibrium Energy of Equilibrium – Energy of molecules depends on – At equilibrium, – Law of Mass Action – An increase in the concentration of reactants tends to push a reaction forward – An increase in the concentration of products tends to push a reaction in reverse Law of Mass Action for Energy-releasing Reaction Law of Mass Action for Energy-requiring Reaction Activation Energy Activation Energy Barrier for Forward and Reverse Reactions Reaching the Transition State Insufficient Energy to Reach the Transition State III. Reaction Rates • Enzymes • • Coenzymes • • Enzyme Affinity • • Allosteric Regulation • • Feedback Inhibition • Reaction Rates Factors Affecting Reaction Rate – Law of Mass Action • Concentration of reactant • • Concentration of product • – Temperature – – Height of Activation Energy Barrier – Role of Enzymes in Chemical Reactions –...
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This note was uploaded on 04/12/2010 for the course BIOL 2160 taught by Professor Kt during the Spring '08 term at LSU.

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Chpt_3_metabolism - Chapter 3 Cell Metabolism This will...

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