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21 Cards in this Set
- Front
- Back
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Enzymes
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proteins that catalyze chemical reactions, they speed up chemical reactions by lowering activation energies
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absolute specificity
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type of enzyme that acts only on 1 substance
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relative specificity
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type of enzyme that acts on structurally related substance; (things that are related)
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stereochemical specificity
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type of enzyme that distinguishes between stereoisomers
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the cell
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regulates enzyme activity and controls the rates of reactions & amount of any product formed
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-in
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the earliest enzymes have names with -___ to indicate their protein composition
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substrate
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the substance that undergoes a chemical change catalyzed by an enzyme
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cofactor
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some enzymes require a second substance present in order to be active which is called a
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coenzyme
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if a cofactor is an organic molecule, it is called a
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apoenzyme
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the catalytically inactive protein formed y the removal of the cofactor
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active enzyme
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apoenzyme + cofactor (coenzyme or inorganic ion) =
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vitamins
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coenzymes are often derived from ______
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active site
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all enzymes have an _______ - the location on the enzyme where a substrate binds and catalysis occurs
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Lock-and-key theory & Induced-fit theory
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2 main theories on active sites
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Lock-and-key theory
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theory on active sites; states that the substrate has a shape that exactly fits the active site, this explains enzyme specificity
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Induced-fit theory
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theory on active sites; states that the conformation of the active site changes to accommodate an incoming substrate
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Enzyme Activity
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the rate at which an enzyme catalyzes a reaction
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turnover number
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the number of substrate molecules acted on by one enzyme molecule per minute
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enzyme international unit
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the quantity of enzyme that catalyzes the conversion of 1 umol of substrate per minute
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optimum temperature
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enzymes have an ___________ range (usually 25-40*C), above or below which they begin to denature
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optimum pH
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enzymes have __________ values (usually around 7), above and below which the rate decreases
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