Bio113_Lecture_4_SLIDES (6 per pg)

Bio113_Lecture_4_SLIDES (6 per pg) - April 3, 2008 Biology...

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1 April 3, 2008 Biology 113, Lecture 4 Biology 113, Lecture 4 Part 1 - Overview Energy transformations and metabolism • ATP, the universal energy currency • Concept of coupling exergonic reactions to endergonic reactions Concepts: 7.5, 8.1, 8.2 and 8.3 Metabolism Chemical reactions of cell provide or consume energy (capacity to do work). An organism ’s metabolism transforms matter and s metabolism transforms matter and energy, subject to energy, subject to the laws of thermodynamics Enzyme 1 Enzyme 2 Enzyme 3 A B C D Reaction 1 Reaction 2 Reaction 3 Starting molecule Product A metabolic pathway has many steps. Catabolism - Breakdown of molecules • Releases energy (e.g., hydrolysis of polymers) Two classes of metabolic pathways Two classes of metabolic pathways Anabolism - Synthesis of complex molecules • Consumes energy (e.g., synthesis of polymers) Thermodynamics Thermodynamics study of energy transformations First law of thermodynamics “Energy can be transferred and transformed but it cannot be created or destroyed .” light energy chemical energy (plants) chemical energy mechanical work (animals) In animals, glucose oxidation provides energy: glucose + 6 O 2 6 CO 2 + 6 H 2 O In contrast, plants synthesis glucose: 6 CO 2 + 6 H 2 Og l u c o s e + 6 O 2 requires energy (light) to drive reaction “energy out” “energy in” Free energy ( Δ G) of a reaction: A + B C + D Δ G is the energy available to do work • Spontaneous reactions have a negative Δ G The free-energy change ( Δ G) of the reaction indicates if a reaction occurs spontaneously Second law of thermodynamics Every process increases the entropy (amount of disorder ) of the universe.
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2 • An exergonic reaction – proceeds with a net release of free energy and is spontaneous Figure 8.6 Exergonic reactions ( Δ G is negative) G is negative) Reactants Products Energy Progress of the reaction Amount of energy released ( G <0) Free energy “downhill” Endergonic Endergonic reactions ( reactions ( Δ G is positive) G is positive) • An endergonic reaction
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This note was uploaded on 04/29/2008 for the course BIO 113 taught by Professor Swenson during the Spring '08 term at Ohio State.

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Bio113_Lecture_4_SLIDES (6 per pg) - April 3, 2008 Biology...

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