Energy and physiology


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How energy and enzyme catalysts relate to exothermic and endothermic reactions.

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Energy and physiology

  1. 1. Energy and Physiology
  2. 2. •Energy is the capacity to do work or cause change •Organisms store energy in organic molecules as chemical energy •Free energy is the portion of energy released during chemical reactions that is available to do work Energy and Nutrients
  3. 3. Energy and Nutrients Organisms obtain their energy through Autotrophy or Heterotrophy Autotrophs are organisms capable of producing their own food Heterotrophs are organisms that must obtain food from an outside source by consuming another organism
  4. 4. Chemical Reactions Make Life Possible! Autotrophs Heterotrophs and Autotrophs
  5. 5. The Law of Conservation of Energy (1st Law of Thermodynamics) •Energy cannot be created or destroyed, but it can change form •The total energy of the universe is constant •Organisms cannot create their own energy but must obtain it from an outside source
  6. 6. The Second Law of Thermodynamics •There is a natural tendency towards disorder “entropy” •Energy is required to resist entropy •An organism must be well organized to remain alive and grow (Organization requires energy)
  7. 7. Chemical Reactions Proceed as Follows: Reactants Products Energy must be added to “activate” the reaction and break the bonds between atoms Activation Energy Metabolism and Energy Transfer
  8. 8. Types of Reactions Endothermic Stores energy in bonds Ex. is photosynthesis
  9. 9. Types of Reactions Exothermic Energy is released by breaking bonds Ex. is cellular respiration
  10. 10. Energy Curve of an Uncatalyzed Exothermic Reaction Energy of Reactants Energy of Products Activation Energy In cases like this (High AE), reactions would occur too slowly to support life!!!
  11. 11. 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! Catalysts
  12. 12. Protein molecules that act as catalysts Specific to a Substance or Reaction Speeds up Biological Reactions to 10,000,000,000 times faster Enzymes
  13. 13. Bind to Specific Reactants to Form a complex Reactants enzymes interact with are called Substrates Substrate binds to the enzyme at a location called the Active Site How Enzymes Work
  14. 14. E + S ES E + P Catalase Breaks H2O2 into H2O and O2 Hydrogen Peroxide is Toxic to Cells Catalase + H2O2 Complex Catalase + H2O + O2 Enzymatic Reactions
  15. 15. Induced Fit
  16. 16. Enzymes are named by taking either the name of the substrate or the action performed and adding the ending “ase” DNA Polymerase Lactase Ligase Naming Enzymes
  17. 17. Factors Effecting Enzyme Action
  18. 18. Metabolism: All the chemical activities in a cell or organism Chemical Reactions in Organisms
  19. 19. Synthesis “building-up” reactions Anabolism; biosynthesis photosynthesis dehydration synthesis
  20. 20. Decomposition “breaking down” reactions Catabolism cellular respiration digestion hydrolysis
  21. 21. Decomposition reactions release free energy Oxidation is the removal of electrons from a molecule Bonds are broken and rearranged Some energy of the original molecule is released as heat and free energy Free energy is finally captured in ATP (adenosine triphosphate) Energy Exchange in Cells
  22. 22. ATP ATP is the cellular energy currency Can store/release small amounts of energy The bond between the 2nd and 3rd phosphate is made or broken to exchange energy