Metabolism: Energy & Enzymes

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Metabolism: Energy & Enzymes
2010-10-19 20:35:02
AP Biology

Chapter 6
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  1. Energy
    - the ability to do work
  2. Kinetic Energy vs Potential Energy
    Energy of Motion vs Stored Energy
  3. First Law of Thermodynamics
    - the law of conservation of energy
  4. Second Law of Thermodynamics
    - energy cannot be changed without a loss of useable energy (heat)
  5. Metabolic Reactions
    Reactants --> Products
  6. Exergonic
    - releases energy
  7. Endergonic
    - absorbs energy
  8. ATP (adenosine triphosphate)
    - the energy currency of cells
  9. Functions of ATP
    • 1. CHEMICAL WORK - Supplies energy needed to make macromolecules that make up the cell (and organism)
    • 2. TRANSPORT WORK - Supplies energy needed to pump substances across the cell membrane
    • 3. MECHANICAL WORK - supplies energy needed to make muscles contract and other cellular parts to move (flagella)
  10. Metabolic Pathways & Enzymes
    • Enzyme - protein molecule that functions as an organic catalyst to speed reactions
    • Substrate - reactants in the enzymatic reaction, this is what an enzyme attaches to
    • Energy of Activation - the energy required to cause the reaction
  11. Properties of Enzymes
    • Enzymes are made of proteins.
    • They speed up chemical reactions inside the cytoplasm.
    • They are needed only in small amounts
    • They remain unchanged after each reaction and can therefore be reused
    • Each enzyme is specific for a substrate
  12. Induced Fit Model
    • - substrates and enzymes fit together like a lock and key.
    • (Degradation vs Synthesis)
  13. Induced Fit Model

  14. Factors Affecting Enzymatic Speed
    • 1. Substrate concentration
    • 2. Temperature & pH
    • 3. Enzyme concentration

  15. Enzymes can be Denatured
    - they change shape so much that they are no longer effective. High temp or pH can cause denaturation.
  16. Enzymatic Inhibition
    - when a substance binds to an enzyme and decreases its activity. (Usually reversible)
  17. Competitive Inhibition
    - binds to the active site of an enzyme, competing with the substrate
  18. Noncompetive Inhibitors
    - binds to another part of an enzyme, causing the enzyme to change shape and making the active site less effective