Plant Physiology 25-35

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ederington
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Plant Physiology 25-35
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2013-09-16 16:43:47
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  1. _____ can be defined as the energy transformations that occur in living organisms, and the flow of that energy through these organisms.
    Bioenergetics
  2. Biological energy transductions (transfers) are based on the _____.
    First two laws of thermodynamics
  3. _____ is the energy of the universe is constant.  This law refers to energy conservation. Energy does not change form.
    First Law of Thermodynamics
  4. _____ says in any physical or chemical process, the amount of entropy tends to increase.  This law states that no energy transformation process is 100% efficient. There is always some quantity of energy that is converted to a form that is no longer useful (lost as heat).
    Second Law of Thermodynamics
  5. _____ can be defined as the extent of randomness or disorder in a system.
    Entropy
  6. Natural systems are always moving towards a state of increasing entropy (theoretically, finally terminating in _____), and energy must be put into the system in order to stop the trend towards increased entropy.
    Entropic doom
  7. The ability of a reaction to accomplish work is based on the principle of _____.
    Free Energy
  8. _____ can be defined as the mean molecular kinetic energy of matter.
    Temperature
  9. Temperature cannot be held constant when this thermal energy is given up, thus the lost thermal energy is considered _____-goes toward entropy increase.
    Isothermally unavailable
  10. Reactions with a negative ΔG are known as _____ reactions, or energy yielding reactions.
    Exergonic (spontaneous)
  11. Reactions with a positive ΔG are known as _____ reactions, or energy consuming/requiring reactions.
    Endergonic
  12. At equilibrium, there will be _____ in the concentrations of reactants and products.
    No net change
  13. The net free energy in coupling reactions must always be _____.
    Negative
  14. Oxidation of a carbon atom in a carbon compound is synonymous with ______ (loss of hydrogen atoms bonded to carbon).
    Dehydrogenation
  15. In cells, electrons can be transferred from one molecule to another in four different ways:
    • 1. directly as electrons
    • 2. as a hydrogen atom (1 electron & 1 proton)
    • 3. as a hydride ion (2 electrons & 1 proton)
    • 4. as a direct combination of an organic reductant with oxygen, producing a molecular product in which oxygen is covalently bonded
  16. Photosynthesis and respiration are primarily a sequence of electrochemical reactions, mostly consisting of a series of _____ and _____ reactions, or _____ reactions.
    Oxidation and reduction

    Redox
  17. Each redox reaction can be conveniently dissected into 2 half reactions involving the _____ and _____ of one or more electrons.
    Donation and acceptance
  18. The electron donor becomes _____.
    Oxidized
  19. The electron acceptor becomes ______.
    Reduced
  20. A reduced/oxidized pair is known as a _____.
    Redox couple
  21. The ability of a molecular species to accept electrons from, or donate electrons to another molecule, is known as its _____.
    redox potential
  22. When a redox couple is 50% reduced, this is known as the _____.
    Midpoint potential
  23. There are 4 primary reasons why ATP will spontaneously hydrolize into ADP and Pi:
    • 1. electron repulsion amongst the four negative charges is somewhat relieved by charge separation after hydrolysis
    • 2. inorganic phosphate (Pi) released by hydrolysis is stabilized by resonance hybride which does not allow H+ to bond to the oxygen atoms of Pi
    • 3. ADP is also immediately ionized and releases a H+ ion into a high pH (7.0) solution
    • 4. ADP and Pi have a higher degree of solvation (hydration) in water than does ATP; this further stabilizes products over reactants.
  24. Under conditions that define standard free energy change, the mass-action ration for ATP hydrolysis is _____ than equilibrium.
    Five orders of magnitude less
  25. The maintenance of a steady-state system is known as _____.
    Homeostasis
  26. ATP links _____ (breakdown of biomolecules into smaller precursors) and _____ (building of biomolecules in the cell.
    Catabolism

    Anabolism
  27. ATP is used primarily for the following processes:
    • 1. synthesis of metabolic intermediates and macromolecules from smaller precursors (anabolism).
    • 2. transport of substances across membranes against concentration gradients (active transport)
    • 3. phosphorylation of biomolecules and group transfer reactions
    • 4. energy storage
    • 5. mechanical motion
  28. The exergonic reaction of ATP hydrolysis actually occurs as a _____ step process.
    Two
  29. Phosphorylated compounds can have a high or low _____, depending of how effectively they can be used to phosphorylate other compounds.
    Phosphate group transfer potential
  30. A group of enzymes known as _____ catalyze the phosphorylation of certain molecules by ATP.
    Kinases
  31. The size and complexity of ATP allows it to form many more favorable _____ between itself and the substrate, over what would be possible with pyrophosphate (PPi).
    Noncovalent interactions
  32. Many noncovalent interactions that are formed increased the _____ (energy derived from the formation of noncovalent interactions) and dramatically increase the rate of reaction.
    Binding energy
  33. _____ is a electrostatic attraction between oppositely charged regions of water molecules, or between two molecules with polar covalent bonds.
    Hydrogen bonding
  34. _____ is an electrostatic interaction between charged groups.
    Ionic interaction
  35. _____ is attractive interactions between non-polar groups.
    Hydrophobic interactions
  36. _____ are attractive forces between large, closely positioned molecules.
    Van der walls forces

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