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Phys 02 14a


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Phys 02 14a

  1. 1. Objective 2.14a – Enzymes <ul><li>Explain what enzymes do, how they participate in metabolism </li></ul>
  2. 2. Metabolism = Biochemistry <ul><li>All the chemical reactions that occur in a living organism </li></ul><ul><li>Chemical reactions, basic processes </li></ul><ul><ul><li>Synthesis: anabolic – building something larger </li></ul></ul><ul><ul><ul><li>Endergonic – requires an input of energy </li></ul></ul></ul><ul><ul><ul><li>A + B  AB </li></ul></ul></ul><ul><ul><li>Decomposition: catabolic – creating smaller products </li></ul></ul><ul><ul><ul><li>Exergonic – releases energy </li></ul></ul></ul><ul><ul><ul><li>AB  A + B </li></ul></ul></ul><ul><ul><li>Exchange: chemical groups are moved around, with no net gains or losses </li></ul></ul><ul><ul><ul><li>AB + CD  AC + BD </li></ul></ul></ul>
  3. 3. Enzymes <ul><li>Proteins that serve as catalysts to the metabolic reaction of cells </li></ul><ul><li>All catalysts (protein, RNA or inorganic) speed up reaction rates </li></ul><ul><ul><li>Active site: pocket of a unique shape that fits only a specific reactant ( substrate ) </li></ul></ul><ul><ul><ul><li>Proper orientation, ideal position for reaction </li></ul></ul></ul><ul><ul><li>Speeds up by a billion X the spontaneous rate </li></ul></ul><ul><ul><ul><li>hydrogen peroxide </li></ul></ul></ul><ul><ul><li>Lower activation energy </li></ul></ul><ul><ul><li>1-10,000 reactions per second </li></ul></ul><ul><ul><li>Enzyme is unchanged by the reaction </li></ul></ul>
  4. 4. Enzyme Functionality <ul><li>Highly specific, only recognize one type of substrate </li></ul><ul><li>Very efficient </li></ul><ul><ul><li>speed up reaction up to 10 billion times faster </li></ul></ul><ul><ul><li>Lower activation energy </li></ul></ul>
  5. 5. Enzyme Rules <ul><li>Enzymes lower activation energy – initial investment of energy that allows a reaction to begin </li></ul><ul><ul><li>Wood does not spontaneously burn </li></ul></ul><ul><li>Reactant “AB” can be converted to products A + B, and even though this </li></ul><ul><li>is an exergonic </li></ul><ul><li>(decomposition) </li></ul><ul><li>reaction, there is an </li></ul><ul><li>initial investment of </li></ul><ul><li>energy that must be </li></ul><ul><li>made to push forward </li></ul>
  6. 6. Enzymes & Activation Energy <ul><li>The active site of an enzyme orients the reactants in the enzyme-substrate complex </li></ul><ul><ul><li>Synthesis reaction (endergonic) </li></ul></ul><ul><ul><ul><li>Reactants are positioned to collide in the right direction to form bonds </li></ul></ul></ul><ul><ul><ul><li>Requires less energy to collide the particles than “spontaneous” reaction </li></ul></ul></ul><ul><ul><li>Decomposition reaction (exergonic) </li></ul></ul><ul><ul><ul><li>Reactant is positioned to bend in the right direction to break bonds </li></ul></ul></ul><ul><ul><ul><ul><li>Induced fit </li></ul></ul></ul></ul>