Biology Ch 8

  1. Metabolism
    the totality of an organism's chemical reactions
  2. metabolic pathways
    begins with a specific molecule, which is then altered in a servies of defined steps, resulting in a certain product. Each step of the pathway is catalyzed by a specific enzyme.

    A molecule →Enzyme 1 = Reaction 1 → B Molecule → Enzyme 2 = Reaction 2 → C Molecule → Enzyme 3 = Reaction 3 → D Product
  3. Catabolic pathways
    breakdown pathways
  4. anabolic pathways
    consume energy to build complicated molecules from simpler one
  5. bioenergetics
    the study of how evnery flows throught living organisms
  6. catabolic and anabolic pathways
    break down complexes and realease energy and build compounds to store energy when in excess....downhill and uphill avenues of the matabolic map
  7. Energy
    • capacity to cause change
    • some forms of energy can be used to move matter against forces (gravity, friction)
    • energy exists in various forms and the work of life depends on the ability of cells to transform energy form one form to another
  8. Kinetic Energy
    energy of motion - can be transfered from one object to another - pool player
  9. Thermal energy
    kinetic energy associates with the random movement of atoms or molecules
  10. potential energy
    energy that matter possesses because of its location or structure
  11. chemical energy
    potentioal energy available for release in a chemical reaction
  12. thermodynamics
    • study of energy transformations that occur in a collection of matter
    • 1) system - matter under study
    • 2) surroundings - everything outside the system
    • 3) isolated systems - unable to exchange energy with its surroundings (liquid in a bottle)
    • 4) open system - able to exchange energy with its surroundings
  13. first law of thermodynamics
    • the energy of the universe is constant
    • Energy can be transferred and transformed byt it caoont be created or destroyed (also know as the principle of censervation of energy)
  14. entropy
    measure of disorder or randomness
  15. second law of thermodynamics
    every energy transfer or transformation increases the entropy (disorder) of the universe

    any process that occurs on its own with out input of energy, will increase the entropy of the universe - water flowing downhill, a car rusting, animal giving off heat and CO2
  16. spontaneous
    • a process that can occur without an input of energy
    • for a process to occur spontaneously it must increase the entropy of the universe
  17. nonspontaneous
    prosess that cannot occur without the input of energy
  18. Exergonic reaction
    • "energy outward"
    • net release of free energy because the chemical mixture loses free energy
    • exergonic reactions are those that occur spontaneously
  19. endergonic reaction
    • "energy inward"
    • absorbs free energy from its surroundings
    • stores free energy in its molecules - nonspontaneous
  20. Metabolism and Equilibrium
    • systems at equilibrium have no free energy - not capable of doing work - dead
    • a living cell is not a equilibrium - constant flow of materials in and out of the cell keeps the metabolic pathwas from ever reaching equilibrium - cell continues to work throughout its life
  21. Cell does three kinds of work
    • chemical work - pushing of endergonic reactions - nonspontanious - uphill - making polymers from monomers
    • Transport work - pumping substances across cell membranes against direction of spontaneous movement
    • Mechanical work - contraction of muscle cells, movement of chromosomes during cellular respiration
  22. energy coupling
    • the use of an exergonic process to drive an endergonic one
    • ATP mediates most energy couplings and acts as the immediate source of energy that powers cellular work
  23. ATP
    • adenosine triphosphate
    • contains:
    • ribose (5C) sugar with the nitrogenous base adenine
    • chain of three phosphate groups bonded to it
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  24. Hydrolysis of ATP
    • Reactants =ATP + 1 molecule of water
    • Products = ADP + free phosphate + energy
    • energy release comes from the chemical change to a state of lower free energy
  25. phosphorylated
    when ATP is hydrated and a phosphate group comes off and it added to some other molecule - the recipient of the phosphate group is phosphorylated
  26. How ATP performs work
    a cells proteins harness energy released by ATP hydrolysis to perform the three types of cellular work - chemical, transport, and mechanical
  27. Fermentation
    • partial degradation of sugars without the use of oxygen
    • (catabolic process)
  28. aerobic respiration

    anaerobic repsiration
    oxygen is consumed as a reactant along with organic fuel

    without oxygen - some prokaryotes harvest chemical energy without any oxygen
  29. cellular respiration
    includes both aerobic and anaerobic processes but usually refers to the aerobic process
Card Set
Biology Ch 8
Biology chapter 8 Metabolism