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Cards In This Set
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CELLS HAVE EVOLVED SEVERAL STRATEGIES FOR ISOLATING AND
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ORGAINIZING THIER CHEMICAL REACTIONS
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ONE STRATEGY USED BY BOTH PROKARYOTIC AND EUKARYOTIC CELLS IS TO AGGREGATE THE DIFFERENT ENZYMES REQUIRED TO
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CATALYZE A PARTICULAR SEQUENCE OF REACTIONS INTO LARGE, MULTICOMPONENT COMPLEXES
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SUCH COMPLEXES ARE USED, FOR EXAMPLE
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IN THE SYSTHESIS OF DNA, RNA AND PROTEINS.
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A SECOND STRATEGY, WHICH IS MOST HIGHLY DEVELOPED IN EUCARYOTIC CELLS
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IS TO CONFINE DIFFERENT METABOLIC PROCESSES, AND THE PROTEINS REQUIRED TO PREFORM THEM WITHIN DIFFERENT MEMBRANE ENCLOSED COMPARTMENTS.
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MEMBRANE-ENCLOSED COMPARTMENTS ARE ALSO KNOWN AS
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MEMBRANE ENCLOSED ORGANELLES
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IN EUCARYOTIC CELLS, INTERNAL MEMBRANES CREATE ENCLOSED
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COMPARTMENTS AND ORGANELLES IN WHICH DIFFERENT METABOLLIC PROCESSES ARE SEGREGATED
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EACH COMPARTMENT CONTAINS A UNIQUE SET OF PROTEINS THAT HAVE TO BE TRANSFERRED SELECTIVELY FROM THE CYTOSOL
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WHERE THEY ARE MADE, TO THE COMPARTMENT IN WHICH THEY ARE USED.
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THIS TRANSFER PROCESS CALLED PROTEIN SORTING
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DEPENDS ON SIGNALS BUILT INTO THE AMINO ACID SEQUENCE OF AMINO ACIDS
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IN A EUCARYOTIC CELLS COMMUNICATE WITH ONE ANOTHER BY FORMING
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SMALL MEMBRANE-ENCLOSED SACS CALLED VESICLES
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VESICLES PINCH OFF FROM ONE COMPARTMENT IN A PROCESS CALLED
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VESICULAR TRANSPORT
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VESCULAR TRAFFIC ALSO PROVIDES THE MAIN ROUTES FOR RELEASING PROTEINS FROM THE CELL BY THE PROCESS OF
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EXOCYTOSIS AND IMPORTING THEM BY THE PROCESS OF ENDOCYTOSIS
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PROCARYOTIC CELLS USUALLY CONSISTS OF A SINGLE COMPARTMENT
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THE CYTOSOL, ENCLOSED BY THE PLASMA MEMBRANE
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EUCARYOTIC CELLS ARE ELABORATELY SUBDIVIDED BY
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INTERNAL MEMBRANES
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THESE MEMBRANES CREATE ENCLOSED COMPARTMENTS IN WHICH
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SETS OF ENZYMES CAN OPERATE WITHOUT INTERFERENCE FROM REACTIONS OCCURING IN OTHER COMPARTMENTS
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A CELL FROM THE LINING OF THE INTESTINE CONTAINS THE BASIC
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SET OF ORGANELLES FOUND IN MOST ANIMAL CELLS
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