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Unformatted text preview: Energy Conversions Transferring Energy in Cells Catalysis Lecture 9 Energy and Catalysis Metabolism can be divided into two types of activities: Anabolic reactions link simple molecules together to make complex ones. These are energy-storing reactions. They require energy. Catabolic reactions break down complex molecules into simpler ones. They release energy. Cells must constantly acquire energy from their environment! Energy conversions First Law of Thermodynamics : during any conversion of energy, the total initial energy equals the total final energy. Energy is neither created nor destroyed What drives energy conversions? Not the energy content, because: But the drive of energy to become evenly distributed or dispersed A hot cup of coffee A balloon A swimmer diving into water Second Law of Thermodynamics : Energy spontaneously disperses from being localized to becoming spread out if it is not hindered from doing so (entropy increases). Energy conversions, e.g. chemical reactions only occur if energy disperses in the universe. The dispersing energy is the driving force for energy conversions. Another way to put it: Energy transformations always result in a state of higher probability (a more disordered state) . Examples: coins in a box, cooling coffee To judge biochemical reactions, we need an equation that gives us the amount of energy released to drive a reaction (change in entropy or free energy). How can a cell release free energy (drive a chemical reaction)?...
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This note was uploaded on 11/15/2010 for the course BIOL 110 taught by Professor Unknown during the Fall '09 term at McGill.
- Fall '09