Phys 02 14a
- 1. Objective 2.14a – Enzymes Explain what enzymes do, how they participate in metabolism
- 2. Metabolism = Biochemistry All the chemical reactions that occur in a living organism Chemical reactions, basic processes Synthesis: anabolic – building something larger Endergonic – requires an input of energy A + B AB Decomposition: catabolic – creating smaller products Exergonic – releases energy AB A + B Exchange: chemical groups are moved around, with no net gains or losses AB + CD AC + BD
- 3. Enzymes Proteins that serve as catalysts to the metabolic reaction of cells All catalysts (protein, RNA or inorganic) speed up reaction rates Active site: pocket of a unique shape that fits only a specific reactant ( substrate ) Proper orientation, ideal position for reaction Speeds up by a billion X the spontaneous rate hydrogen peroxide Lower activation energy 1-10,000 reactions per second Enzyme is unchanged by the reaction
- 4. Enzyme Functionality Highly specific, only recognize one type of substrate Very efficient speed up reaction up to 10 billion times faster Lower activation energy
- 5. Enzyme Rules Enzymes lower activation energy – initial investment of energy that allows a reaction to begin Wood does not spontaneously burn Reactant “AB” can be converted to products A + B, and even though this is an exergonic (decomposition) reaction, there is an initial investment of energy that must be made to push forward
- 6. Enzymes & Activation Energy The active site of an enzyme orients the reactants in the enzyme-substrate complex Synthesis reaction (endergonic) Reactants are positioned to collide in the right direction to form bonds Requires less energy to collide the particles than “spontaneous” reaction Decomposition reaction (exergonic) Reactant is positioned to bend in the right direction to break bonds Induced fit