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- 1. Chapter Two TheChemistry of LifeSection 2-4Chemical Reactions and Enzymes
- 2. Chemical ReactionsChemical reaction– a process that changes (or transforms) one set of chemicals into another.examplesA + B î C + DA + B î CA î E + FChemical Reactions
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- 5. Enzyme ActionChemical ReactionsPartsof a reactionReactants are the elements or compounds that enter into (begin) a chemical reaction.Products are the elements or compounds that are produced by (result from) a chemical reaction.Reactants ProductsChemical Reactions
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- 8. Enzyme ActionChemical ReactionsChemicalreactionsalways involve changes in the chemical bonds that join atoms in compounds.Chemical Reactions
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- 11. Enzyme ActionEnergy inReactionsDepending on the number and types of chemical bonds broken and formed, energy may be either releasedorabsorbed by chemical reactions.Chemical Reactions
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- 14. Enzyme ActionEnergy inReactionsRecall (from 2 minutes ago) thatReactants are the elements or compounds that enter into (begin) a chemical reaction.Products are the elements or compounds that are produced by (result from) a chemical reaction.Chemical Reactions
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- 17. Enzyme ActionEnergy inReactionsIf the reactants (the starting conditions) have more energy than the products (the ending conditions), then energy is released (also known as an exothermic reaction).Chemical Reactions
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- 20. Enzyme ActionEnergy inReactionsIf the reactants (the starting conditions) have less energy than the products (the ending conditions), then energy is absorbed(also known as an endothermic reaction).Chemical Reactions
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- 23. Enzyme ActionEndo- andExothermic ReactionsEndothermic ReactionExothermic ReactionEnergy-Releasing ReactionEnergy-Absorbing ReactionActivation energyProductsActivation energyReactantsReactantsProductsChemical Reactions
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- 26. Enzyme ActionEnergy inReactionsActivation energy is the energy needed to get a chemical reaction started. ExamplePaper (cellulose) burns in the presence of oxygen and releases heat and light.Why then aren’t your books all on fire?You need a spark to get the reaction started.Chemical Reactions
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- 29. Enzyme ActionEnergy inReactions - factsChemical reactions that release energy often occur spontaneously.Chemical reactions that absorb energy will not occur without a source of energy.Chemical Reactions
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- 32. Enzyme ActionEnergy inReactionsIn reversible reactions, one direction will produce energy, A + B î C + D + energyand the other direction will require energy, C + D + energyî A + BChemical Reactions
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- 36. EnzymesA catalyst isa substance that speeds up the rate of a chemical reaction.A catalyst does this by lowering a reaction’s activation energy.Chemical Reactions
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- 39. Enzyme ActionEnzymesEnzymes areproteins that act as biological catalysts. Enzymes speed up chemical reactions that take place in cells.Like other catalysts, enzymes do this by lowering the activation energy of a reaction.Chemical Reactions
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- 42. Enzyme ActionEnergy diagramof a chemical reactionReaction pathwaywithout enzymeActivation energywithout enzymeActivationenergywith enzymeReactantsReaction pathwaywith enzymeProductsIn terms of energy, what an enzyme (or any catalyst) does to a reaction is to lower the activation energy.
- 43. EnzymesWithout enzymes, thethousands of chemical reactions necessary to sustain life would simply be t o o s l o w.Chemical Reactions
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- 46. Enzyme ActionEnzyme ActionEnzymeswork by creating an ideal environment for the reaction to take place.ProximityOrientationThis reduces the energy needed for the reaction to take place.Chemical Reactions
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- 49. Enzymes ActionEnzyme ActionThereactants of enzyme-catalyzed reactions are known as substrates. Substrates bind to a specific location on the enzyme known as the active site.Chemical Reactions
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- 52. Enzymes ActionEnzyme ActionThisassociation is called the enzyme-substrate complex.The fit between substrate and active site is so precise that it is frequently compared to a “lock and key”.Chemical Reactions
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- 55. Enzymes ActionEnzyme ActionItis the shape of these large enzyme molecules that allows them to function.Changes in pH or temperature can cause changes in an enzyme’s shape that can reduce (or destroy) its effectiveness as a catalyst (read “Analyzing Data” on pg. 51 in your text). (Denaturing the enzyme)Chemical Reactions
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- 59. The end ofChapter Two The Chemistry of Life
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- 64. Chemical Reactions andEnzymes (2-4)Chemical Reactions (today)Energy in Reactions (today)Enzymes (10/9)Enzyme Action (10/9)