8 14 a old bonds are starting to break b d new bond

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Unformatted text preview: needed to start a chemical reacEon is called the free energy of ac1va1on, or ac1va1on energy (EA) •  AcEvaEon energy is oQen supplied in the form of heat from the surroundings Fig. 8-14 A Old bonds are starting to break B D New bond formed C Transition state Free energy A C B D EA Reactants A C B ∆G < O D Products Progress of the reaction How Enzymes Lower the EA Barrier •  Enzymes catalyze reacEons by lowering the EA barrier •  Enzymes do not affect the change in free energy (∆G); instead, they hasten reacEons that would occur eventually Fig. 8-15 Course of reaction without enzyme EA without enzyme EA with enzyme is lower Free energy Reactants Course of reaction with enzyme ∆G is unaffected by enzyme Products Progress of the reaction Where substrate binds and where the chemistry occurs Substrate Specificity of Enzymes •  The reactant that an enzyme acts on is called the enzyme’s substrate •  The enzyme binds to its substrate, forming an enzyme‐substra...
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This note was uploaded on 02/27/2010 for the course BIO 1A taught by Professor Schlissel during the Spring '08 term at University of California, Berkeley.

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