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23 Cards in this Set
- Front
- Back
- 3rd side (hint)
what must the value of ∆G be for a reaction to be spontaneous
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negative
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None
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upon what does ∆G depend?
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reactants and products, not pathway
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None
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how is ∆G related to rate of reaction?
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∆G is never related to rate, only if reaction will go or not
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None
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what determines the rate of the reaction?
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the pathway between reactants and products (activation energy)
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if the concentration of substrate in a reaction is increased, what happens to the rate?
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it increases
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as the activation gets greater, what happens to the rate?
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it decreases
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what is often used to stabilize high-energy intermediates in reactions?
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enzyme
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what kind of bonds do enzymes form with the reaction intermediate?
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non-covalent bonds
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what is the name of the site in the enzyme in which the substrate binds?
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active site
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what is the shape of the graph when you graph the relationship of reaction velocity and substrate concentration
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hyperbolic
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what is the definition of Km?
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substrate concentration at which velocity = 1/2 max velocity
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what does a low Km value tell us about the enzyme-substrate relationship?
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efficient enzyme, high enzyme affinity for substrate
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what are the two major classes of enzyme inhibitors?
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competitive and non-competitive
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which enzyme inhibitors bind at the same site as the normal substrate?
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competitive
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what effect do competitive inhibitors have on Km? Vmax?
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increases Km, no effect on Vmax
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what effect do non-competitive inhibitors have on Km? Vmax?
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reduces Vmax, no change in Km
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what does Ki measure?
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affinity of inhibitor for substrate
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for a competitive inhibitor, when the concentration of inhibitor equals Ki, what is the relationship between substrate and Vmax?
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it take 2x as much substrate to reach Vmax/2, or Km is doubled
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for a non-competitive inhibitor, when the concentration of the inhibitor equals Ki, what is the relationship between velocity and substrate?
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velocity is reduced by factor of 2 at every substrate concentration
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what is the relationship of ∆G for forward and backwards reactions?
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∆G has the same magnitude and opposite sign for reversible reactions
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None
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how are ∆G values combined for coupled reactions?
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additive
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None
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does standard free Energy depend on concentration or reactants and temperature of reaction?
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no, it is independent of those factors. It is specific to reactants and products
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can more than two reactions be coupled at once?
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yes.
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