BIO 315 CH 3

  1. Bioenergetics
    the study of the various types of energy transformations that occur in living organisms
  2. energy
    • the capacity to do work, or the capacity to change or move something
    • a) electrical energy can be transduced to mechanical energy when we plug in a clock
    • b) chemical energy is converted to mechanical energy when heat is released during muscle contraction
    • c) fireflies and luminous fish are able to convert chemical energy back to light
  3. The First Law of Thermodynamics
    energy can neither be created nor destroyed, it can only change forms
  4. transduction
    • the change from one form of energy to another
    • *photosynthesis is the most important energy ~ in the biological world; sunlight to chemical energy
  5. The Second Law of Thermodynamics
    expresses the concept that events in the universe have direction; they tend to proceed "downhill" from a state of higher energy to a state of lower energy
  6. Free Energy
    (delta) G - the maximum amount of energy that can be passed on for use in another process
  7. exergonic
    • processes that can occur spontaneously, that is, processes that have a negative delta G
    • favors the formation of products
  8. endergonic
    • processes that are thermodynamically unfavorable, that is, they have a positive delta G (non spontaneous, you must put energy in)
    • favors the formation of reactants
  9. enzymes
    • are catalyst that speed up chemical reactions (accelerate bond-breaking/forming processes)
    • are almost always proteins
    • may be conjugated with nonprotein components
  10. cofactors
    • inorganic enzyme conjugates (nonprotein components)
    • most are metals - Zinc is important, also Iron, Magnesium
  11. coenzymes
    organic enzyme conjugates; Vitamins
  12. Properties of Enzymes
    • Are present in cells in small amounts
    • Are not permanently altered during the course of a reaction (can participate repeatedly)
    • Cannot affect the thermodynamics of reactions, only the rates
    • Are highly specific for their particular reactants called substrates
    • Produce only appropriate metabolic products
    • Can be regulated to meet the needs of a cell
  13. transition state
    • reactants that are at the crest of the energy hump and ready to be converted to products are said to be at the ~
    • few substrate molecules can reach this without an enzyme or catalyst
    • compounds that resemble the ~ tend to be very effective inhibitors (they can bind tightly to the catalytic region of the enzyme
Card Set
BIO 315 CH 3
Cell Biology