Determining the Influence of pH on the Activity of Catalase Enzyme in Potato Tuber Cells

Essay by weronika050891 January 2009

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INTRODUCTIONEnzymes are vitally important for every living organism, because without them the reactions within the cells would occur to slow to sustain life. However there are many factors which affect the rate of enzymes reactions. One of them is pH, which influence on the enzyme activity will be the subject of this investigation. Catalase of potato tuber cells will be the enzyme used in the experiment.

RESEARCH QUESTIONWhat is the influence of different values of pH on the activity of catalase in potato tuber cells?VARIABLESIndependent: potato discs treatment (placing them into buffer solutions of different pH values, mixed with hydrogen peroxide)Dependent: the activity of the catalase, reflected by the rate at which oxygen is evolved, measured at every time the pH is changed.

Controlled: whether the potato discs were chemically threaten, whether the catalase and hydrogen peroxide concentration was the same in every sample ( whether the potato discs were accurately cut and whether they all came from the same potato, whether the same fresh hydrogen peroxide was used in all samples) and whether the temperature remained the same during the whole experiment.

HYPOTHESISDifferent pH values influence the activity of catalase. It was obtained from the literature, that the range of pH values, at which catalase works is approximately 4 to 9, with an optimum pH of 7. Bearing this in mind the following hypothesis has been made:If the potato discs are placed into a test tube with hydrogen peroxide and a buffer solution at pH approximately 7, then the activity of catalase will be the greatest. If the pH value is less or more than 7 the activity of the enzyme will be smaller.

THEORYAn enzyme is a biological catalyst. This means that it's a substance, produced in living organisms, which speeds up a certain reaction, because it lowers...