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23 Cards in this Set
- Front
- Back
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Exergonic reactions
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release of energy in the form of ATP
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Small changes in the catabolism/anabolism cycles affect what?
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metabolism
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T/F - Cycles require less energy than linear
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True
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Catabolism
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Usually uses oxygen.
Degradative reactions of carbohydrates, lipids, and proteints into usable or storage forms of energy. Conversion of complex molecules into small molecules. |
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Anabolism
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Chemical reactions leading to the formation of large, complex macromolecules from smaller precursors.
Requires expenditure of energy in the form of ATP or NADH |
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T/F - There is very little energy in the Mg bond
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False - lots of energy
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The first law of thermodynamics
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the total energy of a system and its surroundings are constant
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What can ΔE no be used to predict?
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Can not predict if a reaction will proceed spontaneously because the equation does not take into account the surrounding.
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First law of thermodynamics (equation):
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ΔE=Eend-Estart=Q(heat)-W(work)
Heat transfer occurs |
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What is entropy
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Order or disorder
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The second law of thermodynamics
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A process can occur spontaneously only if the sum of the entropies of the systems and its surroundings increases.
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Second law of thermodynamics (equation)
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ΔSsystem + ΔSsurroundings > 0
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Diffusion of heat follows what law of thermodynamics?
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Second
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Diffusion of concentrated particles follows what law of thermodynamics?
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Second
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What are the two problems of using entropy as an indicator of spontaneity?
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1) Entropy changes are not readily measured.
2) Requires the knowledge of the entropy change of surroundings as well as the system of interest. |
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What would be an alternative to using entropy as a predictor of spontaneity?
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Use free energy as a predictor. It combines both ΔE and ΔS.
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What is the equation for Gibbs Free Energy?
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ΔG=ΔH-TΔS
ΔG = Change in free energy of a system undergoing a transformation at constant pressure (P) and temperature (T) ΔH = Change in enthalpy of the system ΔS = Change in entropy of the system (properties of the surroundings do not enter the equation) ΔH = ΔE + PΔV since ΔV is small for all biochemical reactions: ΔH=ΔE yielding: ΔG=ΔE-TΔS |
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What does the Gibbs Free Energy equation show?
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The equation shows that change in free energy (ΔG) of the reaction depends on both the change in internal energy (ΔE) and entropy (ΔS) of the system.
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Under the Gibbs Free Energy: Under what conditions can a reaction occur spontaneously?
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Only if ΔG is negative
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Under the Gibbs Free Energy: Under what conditions is a system at equilibrium and not net change can take place?
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If ΔG = 0
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Under the Gibbs Free Energy: Under what conditions can not occur spontaneously?
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If ΔG is positive. An input of energy is required to drive the reaction.
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What does ΔG depend upon?
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The free energy of the products (final state), the reactants (initial state) not on the path of transformation.
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What does ΔG provide no information on?
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The rate of the reaction
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