OCR AS Level Biology Enzymes

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  • Created by: Sorcha
  • Created on: 08-04-13 13:46
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  • ENZYMES
    • Structure
      • Well developed tertiary structure
      • increase the reaction rate without becoming changed - BIOLOGICAL CATALYSTS
      • Can be INTRACELLUAR (act inside the cell) or EXTRACELLULAR (acts outside the cell e.g. digestive enzymes)
      • Globular Proteins
      • have an ACTIVE SITE for substrates to fit too.
        • substrate is complementary to the active site forming a ENZYME - SUBSTRATE COMPLEX
    • Activation Energy
      • the substrate cannot become the product without EXTRA ENERGY
      • You increase the energy by heating it
        • but body temperature cannot increase past 37degrees
      • therefore they DECREASE the activation energy
      • this is by holding the substrate in a particular way allowing the reaction to be easier and at a lower temperature
    • Enzyme Inhibitors
      • Active Site Inhibition
        • Non Competitive e.g. Penicillin
          • Binds permanently to the active site
          • Permanently blocks the active site to the substrate
          • NO COMPETITION OCCURS
        • Competitive e.g. Antifreeze
          • Reversible
          • Inhibitor binds briefly to the active site
          • there is competition between the substrate and the inhibitor for the active site
      • Non-active site inhibition
        • Non-Competitive Irreversible Inhibition e.g. Digitalis
          • The 3D shape is permanently distorted
          • Binds to the enzyme permanently
          • No Binding can occur
        • Non-Competitive Reversible Inhibition
          • the 3D shape is distorted briefly
          • Inhibitor briefly binds to another part of the Enzyme
          • Used to control metabolic reactions in the body
      • WHY?! to regulate metabolic pathways and prevent build up of substances.  To produce Toxins and Venoms

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