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PRACTICAL- ENZVlViE CONCENTRA'l'ION AND RATE OFREACTION 0 (j

I~ ~() /AIM: To investigate the effect or a reduction in enzyme concentration on the rate of reaction bymeasuring the initial rate of reaction,

BACKGROUND: the viscosity of afixed volume!of gelatine cail be determined by the timetaken for the jelly to drain through afunnel. if the gelatine is treated withthe enzyme pepsin and the viscosity determined this will give a rneasureC?fhe breakdown (l the protein by fhe enzyme.

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HYPOTHESIS: (what do you think will be the relationship ~etween protease.concentrationand the rate of breakdown of protein in gelatine? Use scientific ideas tosupport your prediction). , r-,

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APPARATUS LIST:J/. 75g of2% gelatine solution (fully set) pH 2.8 bufTer pepsin solu~ion (5%). Funnel 2 pipcttcs1 stopclock test tubes

41 Test tube rack spatula. 2 X 250cm3 beakers41 Glassware for diluting enzymcs eye protection

METHOD1. Suspend a funnel over an empty beaker.2. Pipette 3cm3 of pH 2.8 bufTcr into a test tubc and place in a test tube rack.3. Pipette 7cm3 of5% pepsin solution into the test tube.

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4. Stm1thc stopclock as themixture in the test tube is poured into a beaker containing 75gof gelatine. Stir the contcnts gently for 15seconds using a spatula then leave for 5minutes to stand.

5. Pour the mixture into the funnel using the spatula to empty the beaker.6. Restart the stopclock as the first drip Icavcs the funnel. Rccord the time taken for all

the gelatine to pass through the funnel.7. Repeat the test twice more and calculate an average time.8. Repeat the experiment with a range of different enzyine concentrations by diluting the

5% pepsin solution (see below)./i

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~ .RISKASSESSMENT (identify any risks and list safety precautions)Ul i!):';'~'~~"I0oLd.e,)S I, i': ",:1:' !/" ,(,,? I,':,

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