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Catalase and Enzymes Investigation

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The aim is to investigate how the rate of reaction changes with concentration of catalase. Catalase is an enzyme found in the body which is produced by the liver to break down a poisonous chemical, hydrogen peroxide. When catalase reacts with this chemical it breaks down into 2 products, water and oxygen. Potatoes contain catalase enzyme so this was used instead of a liver. Potatoes are easier to cut into pieces and it is also easy to use whereas liver is unpleasant to handle and difficult to cut into regular shapes. Equation: The equation below shows that hydrogen peroxide reacts with the enzyme catalase which produces water and oxygen. Hydrogen Peroxide � Water + Oxygen (Catalase) 2H202 � 2H202 + 02 Plan: To complete this investigation I will follow the steps below: 1. Apparatus List - The equipment used will be listed. 2. My Hypothesis - I will predict the outcome of the investigation. 3. Preliminary Test - A trial run will be done to control factors that may go wrong in the actual test. 4. Safety Points - Rules will be made clear to avoid danger and for health and safety reasons. 5. Surface Areas - The surface areas of the potatoes will be clearly stated which will be used in the experiment. 6. Fair Test - I will explain how to make the experiment a fair test. 7. Controlled Factors - I will show the factors that need to be controlled in order for accurate and reliable results. ...read more.


I have used my preliminary results to decide what range to investigate. I will use more ranges in surface areas. My Method: 1. Collect all the equipment needed. 2. Wear goggles and gloves. 3. Attach the gas syringe on the clamp stand. The gas syringe is the most accurate way to measure the oxygen collected. 4. Cut out 5 pieces from the potato by using a borer so all the pieces will have the same diameter. 5. Use the filter paper to dry the potato pieces as they are quite moist. 6. Use a ruler to get accurate measurements. 7. On a tile, cut the potato pieces using a knife to the lengths of the 5 different surface areas listed previously. 8. Put the potato pieces in separate conical flasks. 9. Pour 20ml of hydrogen peroxide in a measuring cylinder. 10. Pour into the conical flask where the potato piece is. 11. Quickly attach the conical flask to the tube of the gas syringe and start timing. 12. Record the amount of oxygen produced after 90 seconds. 13. Repeat the test for this potato 2 more times. 14. Repeat this for the other potato pieces (Steps 9-13). Table Results: (Table form) Amount of Hydrogen peroxide: 20ml Time taken: 90 seconds Unit: ml or cm� Potato 1 - Whole Potato 2 - Cut in half Potato 3 - Cut in thirds Potato 4 - Cut in quarters Potato 5 - Mashed up Test 1 17 13 18 15 21 Test 2 19 10 18 13 21 Test 3 20 12 19 14 20 Average 19 12 18 14 21 I collected the data of the amount of oxygen produced (in ml or cm�) ...read more.


Here are some improvements I can make in order to make my results more accurate and reliable: * The same type or kind of potato should be used in the investigation so it contains the same quantity of catalase enzyme in order to have a fair test and accurate results * After the potato pieces have been cut by a borer, cut by a knife when measured by a ruler (to get the right surface area) weigh the potato pieces to find out the mass as all the pieces should still weigh the same for the investigation to be accurate * During the experiment, shake the conical flask the same amount of times for each different surface area of the potatoes being tested as this will speed up the reaction and this will give another set of reliable results 3. I have evaluated my conclusion In my conclusion, I have fully explained the results by using the data I collected in a table, a graph and my knowledge on the lock and key. When doing the experiment, I carefully carried out the procedure to aim for reliable results. Also, the line of best fit or the trend line showed positive correlation but wasn't as strong which means the data collected was not accurate as possible. So in future, I will record the masses of the potato pieces and make sure they all weigh the same even though they all have different surface areas. Plus, the experiment will be repeated several more times. This will give a better outcome of the data collected which makes the conclusion have an enhanced description or explanation. Therefore, the whole investigation and its aim will be performed successfully. ?? ?? ?? ?? 1 ...read more.

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