Ch 6

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Author:
khonka
ID:
40564
Filename:
Ch 6
Updated:
2010-10-10 23:48:09
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Bio
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Description:
An intro to Energy
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  1. Energy
    • the capacity to bring about movement against an opposing force.
    • Maintain their organization
    • Carry out reactions that allow cells to develop, grow, and reproduce
  2. Potential energy
    is stored energy with the capacity to perform work
  3. Kinetic energy
    • energy of motion; energy that is actually doing work
    • ex. heat, light, running, a ball rolling
  4. Chemical energy
    • potential energy of molecules that held in the chemical bonds (covalent bonds)
    • ex. food, storage of molecules such as starch, glycogen, fat
  5. Thermodynamics
    the study of energy.
  6. First law of Thermodynamics
    • The energy is never created or destroyed, but is only transformed(from one form to another)
    • Amount of energy in the universe is constant. Some energy is stored in the chemical bonds and the rest of the energy is lost to heat ( or converted to heat)
  7. The second law of thermodynamics
    • Energy cannot be changed from one form to another without a loss of usable energy
    • Each energy conversion results in an increase in disorder, or randomness. (in yielding energy, matter goes from a more-ordered state to a less-ordered state or to disordered, dispersed energy of heat.
  8. Entropy
    • a measure of the amount ofdisorder in a system. The greater the entropy, the greater the disorder.
    • entropy in the universe is always increasing due to the many energy transformation that take place.
    • Heat, which is random molecular motion, is a form of disorder
  9. Enderognic reactions
    • The build-up of complex molecules from simpler ones
    • Require an input of energy
    • The products contain more energy than the reactants
  10. Exergonic reactions
    • The breakdown of complex molecules into simpler ones
    • Releases energy
    • The products contain less energy than the reactants
  11. Metabolic reactions
    • Reactants: substances that participate in a raction
    • Products: Substances that form as a result of a reaction
  12. Coupled reactions
    a chemical reaction in which an exergonic reaction powers an endergonic reaction
  13. ATP
    • An energy transfer molecule that powers cellular functions
    • ATP has a sugar called ribose and a nitrogen-containig base called adenine. Ribose and adenine make up a compound called adenosine. 3 Phosphate groups are then linked to adenosine. Energy is stored in the phosphate groups. When one phosphate group is released from the ATP the energy is released and ATP becomes ADP
  14. Enzymes
    • proteins that help to speed up chemical reactions, by lowering the amount of energy requried to activate reactions
    • Thousands of specialized enzymes exist
    • Facilitate nearly every chemical process in living things
    • -ase ending of names of enzymes
    • Substrate: the substance that is worked on by an enzyme
    • Have unique three-dimensional shapes
  15. Metabolic pathway
    • a set of enzymatically controlled steps that results in the completion of a product or process in an organism.
    • A serios of linked chemical reactions, controlled by enzymes, that occurs in a cell.
  16. Metabolism
    sum of all the chemical reactions that occur in a cell or organism
  17. Enzymes lowering activation energy
    • enzymes are in the business of lowering the amount of energy needed to get chemical reactions going. It means the reactions can get going faster.
    • activation energy: the energy required to initiate a chemical reaction.
  18. How do enzymes work?
    • an enzyme binds to a substrate, making it more volnurable to chemical alteration(spliting, combinining, rearanging).
    • The enzyme is changed or used up when it participates in the reaction.
    • Ezymes are catalysts: - substaces that retain their original chemical composition while bringing about a change in a substrate
    • Active site: the part of the enzyme that binds with the substrate
  19. CoEnzymes
    • molecules other than amino acids that facilitate the work of enzymes by binding with them.
    • Vitamins transformed into coenzymes that sit in the active site of an enzyme and provide an added chemical attraction or repulsion that allows enzymes to do its job.
  20. Competitive inhibition
    • molecule other than the substrate can bind to the active site.
    • If the active site is occupied, the chemical reaction will not occur
  21. Allosteric regulation
    a molecule binds to a site on the enzume other than the active site and changes the enzyme's activity (by changing the shape of the active site), either increase or reduce its activity.
  22. Factors affecting enzyme activity
    • Temprature:
    • -A temp increase can increase enzyme activity
    • -Very high temps cause enzymes to become denatured or lose their shape
    • pH:
    • -Extreme pH conditions can also cause enzyme denaturation
    • -At low pH, extra hydrogen ions can interfere with chemical bonds in the protein
    • Salinity:
    • -Extra salt ions can interfere with chemical bonds in the protein.
  23. Enzyme inhibitors
    • Pesticides are toxic to insects becuase they inhibit important enzymes in the nervous system
    • Penicillin, an antibiotic, inhibits an enzyme that bacteria use to make cell wall
    • Some herbicids work by interfering with cell membrane production or the synthesis of amino acids.

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