Energy and Organisms


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Thie presentation focuses on major biological concepts from Chapter 2 of BSCB Blue: A Molecular Approach

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Energy and Organisms

  1. 1. Energy and Organisms
  2. 2. Energy and Nutrients <ul><li>Energy is the capacity to do work or cause change </li></ul><ul><li>Organisms store energy in organic molecules as chemical energy </li></ul><ul><li>Free energy is the portion of energy released during chemical reactions that is available to do work </li></ul><ul><li>Organisms obtain their energy through Heterotrophy or Autotrophy </li></ul>
  3. 3. Chemical Reactions Make Life Possible! Autotrophs Heterotrophs and Autotrophs Photosynthesis Cellular Respiration
  4. 6. Energy Flow and Conversions <ul><li>The Law of Conservation of Energy </li></ul><ul><li>Energy cannot be created or destroyed, but it can change form </li></ul><ul><li>The total energy of the universe is constant </li></ul><ul><li>Organisms cannot create their own energy but must obtain it from an outside source </li></ul><ul><li>The Second Law of Thermodynamics </li></ul><ul><li>There is a natural tendency towards disorder “entropy” </li></ul><ul><li>Energy is required to resist entropy </li></ul><ul><li>An organism must be well organized to remain alive and grow (Organization requires energy) </li></ul>
  5. 7. Chemical Reactions Proceed as Follows: Reactants Products Metabolism and Energy Transfer Energy must be added to “ activate ” the reaction and break the bonds between atoms
  6. 8. Under Normal Conditions, a High Amount of Energy is Needed to Start a Reaction Activation Energy In cases like this ( High AE ), reactions would occur too slowly to support life!!! Energy of Reactants Energy of Products
  7. 9. Catalysts Catalysts speed up the rate of a reaction by lowering the activation energy needed to get the reaction going Catalysts are not changed or used up during a reaction!
  8. 10. A Catalyzed Reaction… Requires less energy to get started!!! Energy of Reactants Energy of Products Activation Energy
  9. 11. The Living Cell has Special Molecules Which Act as Catalysts……. Enzymes <ul><li>Protein Biomolecules </li></ul><ul><li>Specific to a Substance or Reaction </li></ul><ul><li>Speeds up Biological Reactions to 10,000,000,000 Times Faster </li></ul>
  10. 12. How do Enzymes Work? Bind to Specific Reactants to Form a Complex Reactants called Substrates Substrate Binds to the Enzyme at the Active Site
  11. 13. Enzymatic Reactions Important Enzyme: Catalase Breaks H 2 O 2 into H 2 O and O 2 Hydrogen Peroxide is Toxic to Cells Enzymes use “induced fit” to help bonds form or break between compounds E + S ES E + P Catalase + H 2 O 2 Complex Catalase + H 2 O + O 2
  12. 14. Naming Enzymes Enzymes are named by taking either the name of the substrate or the action performed and adding the ending “ ase ” <ul><li>DNA Polymerase </li></ul><ul><li>Lactase </li></ul><ul><li>Ligase </li></ul>
  13. 15. Factors Effecting Enzyme Action <ul><li>pH: Measure of Solution (0-14) </li></ul><ul><li> Neutral (pure water) = 7 </li></ul><ul><li> Acids are less than 7, bases more than 7 </li></ul><ul><li>***Each enzyme has its own range of optimal pH </li></ul><ul><li>Temperature: temp = rate </li></ul><ul><li> temp = rate </li></ul><ul><li>***Temperatures too high or low will denature the enzyme! </li></ul>
  14. 16. Chemical Reactions in Organisms Metabolism : All the chemical activities in a cell or organism Synthesis: “building-up” reactions biosynthesis, photosynthesis dehydration synthesis Decomposition: “breaking down” reactions cellular respiration, digestion hydrolysis
  15. 17. Energy Exchange in Cells <ul><li>Decomposition reactions release free energy </li></ul><ul><li>Oxidation is the removal of electrons from a molecule </li></ul><ul><li>Bonds are broken and rearranged </li></ul><ul><li>Some energy of the original molecule is released as heat and free energy </li></ul><ul><li>Free energy is finally captured in ATP (adenosine triphosphate) </li></ul>