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Report on a practical - Investigating catalase activity.

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REPORT ON A PRACTICAL: INVESTIGATING CATALASE ACTIVITY In this experiment I need to find out the factors that affect the rate of reaction of the enzyme catalase. I will need to carry out some background information to find out what may affect my experiment. Introduction: Enzymes are biological catalysts; they speed up the chemical reactions, which go on inside living things. Without them the reactions would be so slow that life would not exist! Enzymes are very efficient at doing their job. For example, in chemical reactions which happen in our cells, (i.e. our liver), they produce a by-product called hydrogen peroxide. Hydrogen peroxide is extremely poisoness so we must get rid of it quickly. Under the influence of an enzyme called catalase, the hydrogen peroxide is broken down into harmless water and oxygen. Catalase acts very quickly; one molecule of it can deal with six million molecules of hydrogen peroxide in one minute. Catalase (from potato discs) = Enzyme Hydrogen Peroxide ---------------------------------- Oxygen & Water = Substrate = Products The properties of an enzyme are as follows: - They are specific in their action: Each enzyme controls one particular reaction or type of reaction. - They can be used over and over again: They are not altered by the reaction in which they take part. However an enzyme molecular eventually runs down and has to be replaced. ...read more.


This is because the hydrogen peroxide will start to become saturated and there will be less hydrogen particles to collide and therefore less oxygen to be produced. Safety: Whilst carrying out this investigation I will have observed and kept to the relevant safety rules. I will have worn goggles to protect the eyes from the hydrogen peroxide. A labatory coat will be worn to prevent chemicals from spoiling clothes. Care will also be taken whilst handling the chemicals, as hydrogen peroxide is corrosive. I will also keep all the apparatus away from the edge of the desk to prevent breakages. Apparatus: - Hydrogen Peroxide - Cork Borer - Water - Scalpel - Bung - Chopping Board - Stop Watch - Beaker - Delivery Tube - Measuring Cylinder - Conical Flasks (2) - Potato - Hydrogen Peroxide (10cm) - Water Diagram: Variables: - Controlled Variable: I must ensure that I keep the temperature the same, the amount of hydrogen peroxide the same amount and exact size of each potato cylinder the same size throughout this experiment, to keep the experiment equally consistent throughout. - Independent Variable: I will keep everything the same as if it was a controlled variable, but I will change one element on each of the experiments -the amount of potato discs used. - Dependant Variable: This is to see the amounts of bubbles resulting in the independent variable that I will have done. ...read more.


- I will constantly monitor all results on each experiment to ensure that I do not miss anything (to ensure that the results will be 100% accurate). Results: The results that I gained from the all 6 experiments are shown in the table below. Experiment Potato Discs Minutes Bubbles Total Hydrogen Peroxide Frequency of a Bubble appearing No 1 5 5 39 10 cm Every 8 seconds No 2 10 5 34 10 cm Every 9 seconds No 3 15 5 62 10 cm Every 5 seconds No 4 20 5 99 10 cm Every 3 seconds No 5 25 5 93 10 cm Every 3.2 seconds No 6 30 5 206 10 cm Every 1.24 seconds Graph: Evaluation of Results: My experiment was successful, but I could do more things in order to get more reliable results. If I had had more time, I would certainly do the experiment more times with different amounts of potato discs. I would have liked to do the experiment using different amounts of the hydrogen peroxide to see the affect it would have had on the same amounts of potato discs that I had already used in the experiments that I had done. According to the results chart and the graph, there are no visible outstanding results. If I had done the experiment more times and got a more precise average, then there may have been some outstanding results (for example, results that were too high or too low in comparison to the majority of the results). ...read more.

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