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16 Cards in this Set
- Front
- Back
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Activation Energy (Ea)
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the initial investment of energy for starting a reaction;
the energy required to break the bonds of the reactants |
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Catalysts
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chemical agents that speed the rate of a chemical reaction without being consumed or changed
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How are catalysts thought to work?
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By lowering the activation energy needed for a reaction to occur.
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Most catalysts in organisms are made up of what?
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Enzymes (proteins)
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What is ribozyme?
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RNA acting as a catalyst for a few biochemical reactions
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Structure of Enzymes:
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Globular proteins.
Simple or conjugated. |
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Depending on the relative concentration of reactants and products, Enzymes can...
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...catalyze a reaction in either direction.
It does not determine the direction |
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What are substrates?
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Reactants in enzyme catalyzed reactions
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Enzymes differ in _____?
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specificity
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2 specificities of enzymes and corresponding meaning
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Very specific- only catalyze one specific type of reaction. (eg urease)
Non-specific -- will catalyze several different, but very similar reactions (eg lipase) |
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Enzymes work primarily based on their _____?
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3D shape, which is distinctive for each type of enzyme.
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What is the active site of an enzyme?
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Portion of an enzyme that interacts with a substrate
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2 theories of active site and substrate fit, and their differences?
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Lock and Key model- enzyme won't change shape.
Induced-fit model (most common) - Enzyme changes shape temporarily |
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3 ways enzymes may help speed up a reaction
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Bringing substrates close together.
Orient substrates correctly for reaction. Weaken bonds in substrate so they will break. |
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3 Environmental factors that affect enzyme reaction rate
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Temperature
pH Inhibition |
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2 types of Inhibitors and their meaning
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Competitive - very similar in structure to the normal substrate; they compete with the normal substrate for binding to the active site.
Non-competitive -- do not resemble the structure of the normal substrate; bind to the allosteric site and change the shape of the enzyme and its active site |
