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21 Cards in this Set
- Front
- Back
Enzyme
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Usually a protein; biological catalyst (unchanged by the reaction, creates potential for reaction), lowers the energy required for a reaction. Have highly ordered 3D shapes for "conformation"
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Enzyme Substrate
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Reactant in the enzyme-catalyzed reaction; fits into specific pocket in the enzyme called an "active site."
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What Factors Affect Enzyme Activity?
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1.Temperature
2.pH 3.Metal Ions 4.Coenzymes: smaller molecules derived from water soluble vitamins |
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Naming Enzymes
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Most end with "ase." Named for function or activity. Phosphatases remove phosphate groups and kinases add them. Lactate hydrogenase specifies enzyme and activity.
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Active Sites
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Pockets that substrates fit into
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Cofactors
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Include metal ions such as Ca2, Mg2, Mn2, Cu2, Zn2
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Coenzymes
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derived from vitamins; transport H atoms; small molecules
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Enzyme Activation
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Produced in inactive form (keeps pancreas from self-digestion), many are activated by phosphorylation and inactivated by dephosphorylation.
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Substrate Concentration
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Rate of production increases as substrate concentration increases until the enzyme is saturated.
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Law of Mass Action
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Direction of reaction is from side of equation where concentration is higher to side where it is lower
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Metabolic Pathways
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Are sequences of enzymatic reactions that begin with initial substrate, progress through intermediates, and end with final product.
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1st Law of Thermodynamics
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Energy can be transformed but not created or destroyed
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2nd Law of Thermodynamics
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Energy transformations increase the degree of disorganization of a system (entropy)
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Free Energy
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Only energy in an organized state can be used to do work
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Endergonic Reactions
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Require input of energy to proceed
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Exergonic Reactions
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Release energy as they proceed
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Reductions
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When a molecule gains an electron (Reducing agent gives up electrons)
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Oxidation
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When a molecule loses an electron (oxidizing agent accepts electrons)
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pH Optimum
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Each enzyme has optimal activity at a characteristic pH called pH Optimum for that enzyme
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Coupled Reactions
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Energy from exergonic reactions are used to drive endergonic reactions to make ATP
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NAD, FAD
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Coenzymes that serve as H carriers, derived from vitamins: Niacin (B3) and Riboflavin (B12). NAD can accept 2 electrons and 1 proton (NADH+H) and FAD can accept 2 P and 2 E (FADH2)
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