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26 Cards in this Set
- Front
- Back
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T or F. All enzymes are proteins
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FALSE RNA can function as a catalyst as well and has the same fundamental properties of protein catalysts
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Describe ATP to ADP + Pi reaction
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ATP is the substrate attacked by water
catalyzed by ATPases to very high energy, unstable transition state Then back to substrate or on to ADP + Pi |
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Does ATP or ADP + Pi have higher free energy
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ATP (our substrate in the reaction)
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What kind of energy do catalysts lower?
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energy of the transition state or activation energy
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Does ATPase alter equilibrium?
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NO catalysts never ALTER equilibrium they just increase the speed to get there
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Why can we use enzymes multiple times?
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because they are not consumed or altered during a reaction
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An enzyme has an "_____ ___" that positions aa R groups in the proper position for catalysis
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active site
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T or F enzymes determine the direction in which a reaction will proceed
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FALSE thermodynamics determine the direction of the reaction
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how can we measure the activity of an enzyme?
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graph amount of product vs time
or graph loss of substrate vs time or look at proportionality of product against time |
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t or false. The reaction velocity scales with the amount used: use twice the amount and you get twice the rate
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TRUE! it's proportional
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T or F. Enzymes are highly specific
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Falso enzymes CAN be highly specific but some are efficient for a large group of compounds and are therefore not very specific
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Are coeznymes and prosthetic groups proteins or nonproteins?
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non proteins
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what is the distinction between a coenzyme and a prosthetic group?
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how tightly bound the group is to the protein
coenzyme dissociation constant 10e-5 prosthetic are covalently bound and cannot be removed easily without damaging the protein 10e-9 |
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def. a term for an enzyme from which a coenzyme or prostehtic group is missing
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apoenzyme
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apoenzyme + coenzyme (prosthetic group) =
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holoenzyme (active!)
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T or F. metal ions can be essential parts of enzymes
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True!
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what kinds of metal ions are essent to enzymes
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iron
mg cobalt others in porphyrins |
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what metal ions are essential to the activity of various enzymes and are generally tightly bound
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zinc
manganese molybdenum copper |
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What metal ions are loosely bound and need high concentrations
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free mg
ca potassium |
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A ______ can be a simple inorganic compound or a biological macromolecule called an enzyme
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catalyst
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catalysts work by stabilizing the __________ ______ of a chemical reaction which lower the activation
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transition state
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T of F. A catalyst can increase the relative rate significantly with very little Ea
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TRUE!
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Does an enzyme catalyze only the forward reaction?
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NO because the free energy difference between reactants and products of a reaction and the starting concentration of each determines the direction
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most enzymes use ____ fit model
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induced
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many enzymes bind non protein cellular components that are used as key factors in the enzyme activity. These fall into three basic categories....
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metals
coenzymes prosthetic groups |
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def. low molecular organic compounds that bind either weakly or tightly to the protein.
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coenzymes and prosthetic groups
coenzyme weak prosthetics tight! |
