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Discover the affects of PH on the enzyme catalase.

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Aim The aim of this investigation is to discover the affects of PH on the enzyme catalase Introduction: Catalase- This is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from cells. Hydrogen Peroxide is the poisonous by-product of metabolism. It speeds up the decomposition of hydrogen Peroxide into oxygen and water. It is able to do this because the shape of its active site matches the shape of Hydrogen Peroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is an ANABOLIC REACTION. BACKGROUND INFORMATION ON ENZYMES: Enzymes- Enzymes are complex 3-D globular proteins, some of which have other associated molecules. Enzymes are a catalyst which alters the rate of chemical reaction without itself undergoing a permanent change, and therefore can be used over and over again. Enzymes help reactions speed up which would otherwise take place very slowly. ...read more.


The rest of the variables will be kept constant and only the temperatures will be changed. Apparatus To test how the PH affects the rate of reaction, I will use the following apparatus: * Gas syringe through bung * Potato * Hydrogen Peroxide * Stop Clock * Cork borer * Scalpel * water Beaker-250 cm� * Delivery Tube * Ph 3,5,7,9 * 5 cm� or 10 cm� plastic syringe with end cut off * measuring cylinder * conical flask * White tile * wax * Test tubes * Test tube rack * Safety equipment; goggles, lab coat, gloves Alternative: Use yeast, broad beans or liver, instead of potato and apple. Method 1. Measure out 5cm3 of potato into a conical flask 2. Measure out 10 cm3 of buffer solution into a separate container and mix it with minced potato. 3. Measure out 5cm3 volume of hydrogen peroxide in syringe. 4. ...read more.


10.0 17.35 2.0 240 1.5 11.1 20.15 2.0 270 1.5 13.6 24.15 2.0 300 1.5 14.0 31.15 2.0 These results clarify that the optimum ph for catalase is 7 which supports my prediction. At the lowest ph 3, less oxygen was released, measuring a slower rate of reaction. My background information explains this. The enzyme don't work as it is neared extreme PHS. This is because its shape would have been change slightly; means the active site may not fit into the substrate any more. Further investigation: If this investigation were to be done again, I would take all results myself and use my own interpretation, thus gaining more reliable results. I will know how much potato to measure out for each experiment and also I will make sure that the other variables are kept constant. I have taken the same amount of each, keeping them constant. This would give me clearer results to aid me in my understanding as to how ph can affect the activity of catalase. Saira ...read more.

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