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Chemical Reactions and Enzymes. . Reactant. Product. +. Product. Chemical Reactions. An interaction between 2 chemicals – chemical bonds are either broken or formed. The two parts of a chemical reaction are the REACTANTS and the PRODUCTS . . Reactant. +. Reactant. Product. .
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Reactant Product + Product Chemical Reactions • An interaction between 2 chemicals – chemical bonds are either broken or formed. • The two parts of a chemical reaction are the REACTANTS and the PRODUCTS. Reactant + Reactant Product
Chemical reactions & energy • Some chemical reactions release energy • digesting polymers • Some chemical reactions require input of energy • building polymers
Chemical Reactions • Activation Energy - the energy needed for a chemical reaction to start • Most reactions in our bodies require high energy to occur quickly enough to keep a cell working properly. reactants energy released by the reaction products
ENZYMES Enzymes are catalysts! Enzymes are proteins that do the body’s work! Enzymes speed up chemical reactions by interacting with substrates to lessen the energy needed … Most enzymes have names that end in “-ase”
Enzymes Act On Specific Substrates • Enzymes have specific shapes! • A specific substrate (the reactants) will fit in the enzyme’s active site. • Enzyme + Substrate: fit like a lock-and-key (called “induced fit”).
Enzymes Work By Lowering Activation Energy • Activation Energy is the energy needed to start a chemical reaction (An energy bump you must jump over to get going). • Ex: pushing a rock downhill (The enzyme acts as a crowbar)
Draw the energy graph below: activation energy without enzyme reactants activation energy with enzyme energy released by the reaction Question: What affect does an enzyme have? products
Four Features of Enzymes 1) Enzymes make reactions happen faster (they are catalysts) 2) Reactions do not alter or use up enzyme molecules
Four Features of Enzymes 3) The same enzyme usually works for both the forward and reverse reactions 4) Each enzyme has a specific shape and recognizes (and binds to) a specific substrate
Factors That Influence Enzyme Activity Temperature pH Salt Concentration
Effect of Temperature • Small increase in temperature increases molecular collisions, reaction rates • High temperatures disrupt bonds and destroy the shape of active site
Effect of pH Which curve likely represents an enzyme in the stomach? Why? Which curve likely represents an enzyme in the blood? Why?