Enzyme Experiment
...g tubes as the readings for the results will be wrong if this is not constant. · Use the same method for each experiment so that there won´t be any major differences. Only alter the temperature. · Keep the amount of potato the same amount. · Measure the temperature with a thermometer. Accuracy In order to make my investigation go to plan I will be as accurate as I can be so I will measure to the correct measuring size. · Measure the volume in cm³ and amount of potato in grams to make sure that they are exactly the same mass before using them in the experiment. · Do the experiment three times to ensure that there isn´t an odd result. Three is a good number to use as you can see if there is one odd one where if you just done the experiment twice then you wouldn´t know which one odd and which isn´t. · Also to average out the results. Safety precautions · Wear goggles · Tuck tie in skirt · Wear work shirt · Handle the hydrogen peroxide with care as it is corrosive and an irritant From my research I think that the enzymes will denature after 40ºC and any other temperature above that. Reason being that enzymes are proteins and their structure is three-dimensional. Increasing the temperature disturbs the intra molecular bonds that hold the 3D shape. Because of this the shape is altered. Enzymes have an active site. This fits into the substrate molecular (see diagram2-lock and key). If the active site is altered the substrate will no longer fit in and so the enzyme doesn´t work properly. The rise of reaction rate is also due to the increase in temperature, relating to the kinetic theory. The higher the temperature, the faster they move. This happens but only to an optimum of 40ºC. The curve leading up to the optimum point is gradual but as it is reached it falls dramatically. The reason being that the active site is destroyed therefore no reaction can take place as there is only one specific active site per substrate. OBTAINING EVIDENCE Below are my table of results which show the height of froth produced in cm and the volume of oxygen in cm³ for each of the three tests at each of the five temperatures studied. TEMPERATURE: 10ºC TEST 1 TEST2 2 TEST 3 TIME (mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 3 3 2.4 9 2 4 1 3.7 6 3 10 3 8 1.5 4.2 8 3.3 11 4.3 12 2 4.8 10 3.5 12 5.4 12 2.5 5.3 11 3.9 13 6 12 3 5.7 12 4 13 6.2 13 3.5 6.5 12 4.2 13 7.4 13 4 6.8 13 4.4 13 8 14 4.5 7.5 13 4.4 13 8 14 5 8.2 13 4.4 13 8 14 TEMPERATURE: 25ºC TEST 1 TEST2 2 TEST 3 TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 3 9 4 5 3 8 1 5 14 6 10 4.9 12 1.5 6 18 6.5 14 5.8 15 2 7.5 20 7 18 7.6 19 2.5 9 20 8 20 8.2 20 3 10 20 9 21 9.1 21 3.5 10 20 9 21 10 22 4 10 20 9 21 10 22 4.5 10 20 9 21 10 22 5 10 20 9 21 10 22 TEMPERATURE: 37ºC TEST 1 TEST2 2 TEST 3 TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 4 7 5 12 4.5 10 1 5.5 14 8 20 6 16 1.5 7 19 10 26 8 22 2 9 22 11 28 10 26 2.5 10 28 12 30 11 28 3 10 28 12 30 11 28 3.5 10 28 12 30 11 28 4 10 28 12 30 11 28 4.5 10 28 12 30 11 28 5 10 28 12 30 11 28 TEMPERATURE: 55ºC TEST 1 TEST2 2 TEST 3 TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 4 12 5 14 6 15 1 6 18 6 19 7 20 1.5 7 22 6.5 22 8 22 2 8 24 8 24 8 24 2.5 8 25 8 25 8 25 3 8 26 8 25 8 26 3.5 8 26 8 26 8 26 4 8 26 8 26 8 26 4.5 8 26 8 26 8 26 5 8 26 8 26 8 26 TEMPERATURE : 100ºC TEST 1 TEST2 2 TEST 3 TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 0.1 0.5 0.1 1 0.1 1 1 0.1 0.5 0.1 1 0.1 1 1.5 0.1 0.5 0.1 1 0.1 1 2 0.1 0.5 0.1 1 0.1 1 2.5 0.1 0.5 0.1 1 0.1 1 3 0.1 0.5 0.1 1 0.1 1 3.5 0.1 0.5 0.1 1 0.1 1 4 0.1 0.5 0.1 1 0.1 1 4.5 0.1 0.5 0.1 1 0.1 1 5 0.1 0.5 0.1 1 0.1 1 AVERAGES Table of averages from each of the above temperatures TEMPERATURE: 10ºC TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 2.5 5.0 1 3.2 8.0 1.5 3.9 10.3 2 4.6 11.3 2.5 5.1 12.0 3 5.3 12.7 3.5 6.0 12.7 4 6.4 13.3 4.5 6.6 13.3 5 6.9 13.3 TEMPERATURE: 25ºC TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 3.3 7.3 1 5.3 12.0 1.5 6.1 15.7 2 7.4 19.0 2.5 8.4 20.0 3 9.4 20.6 3.5 9.7 21.0 4 9.7 21.0 4.5 9.7 21.0 5 9.7 21.0 TEMPERATURE: 37ºC TIME(mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 4.5 9.7 1 6.5 16.6 1.5 8.5 22.3 2 10 25.3 2.5 10 28.7 3 10 28.7 3.5 10 28.7 4 10 28.7 4.5 10 28.7 5 10 28.7 TEMPERATURE: 55ºC TIME (mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 5.0 13.7 1 6.3 19.0 1.5 7.1 22.0 2 8.0 24.0 2.5 8.0 25.0 3 8.0 25.7 3.5 8.0 26.0 4 8.0 26.0 4.5 8.0 26.0 5 8.0 26.0 TEMPERATURE: 100ºC TIME (mins) HEIGHT OF FROTHcm VOLUMEOF OXYGEN(cm³) 0.5 0.1 0.83 1 0.1 0.83 1.5 0.1 0.83 2 0.1 0.83 2.5 0.1 0.83 3 0.1 0.83 3.5 0.1 0.83 4 0.1 0.83 4.5 0.1 0.83 5 0.1 0.83 These two tables show the average measurement that we recorded for each temperature. HEIGHT Time (mins) Temperature (ºC) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 10ºC 0 2.5 3.2 3.9 4.6 5.0 5.3 6.0 6.4 6.6 6.9 25ºC 0 3.3 5.3 6.1 7.4 8.4 9.4 9.4 9.4 9.4 9.4 37ºC 0 4.5 6.5 8.5 10 10 10 10 10 10 10 55ºC 0 5.0 6.3 7.1 8 8 8 8 8 8 8 100ºC 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 VOLUME Time (mins) Temperature (ºC) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 10ºC 0 5.3 8 10.3 11.3 12 12.7 12.7 13.3 13.3 13.3 25ºC 0 7.3 12 26.7 19 20 20.6 21 21 21 21 37ºC 0 9.7 16.6 22.3 25.3 26.7 26.7 26.7 26.7 26.7 26.7 55ºC 0 13.7 19 22 24 25 26.7 26 26 26 26 100ºC 0 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Analysing results and Conclusion From my results it appears that catalase works best at 37ºC, and it is virtually denatured at boiling point. Looking at the initial part of the reaction (see graph 1) it is clear that the gradient at the beginning gets steeper when looking at the temperatures between 10ºC-55ºC. At each temperature the line levels off towards the end of five minutes. Looking at graph 2, there is a steady rise in height of froth up to 37ºC and then a gradual fall up to 100ºC. Looking at my background knowledge and prior experiments using enzymes I can explain my results as follows. Kinetic theory states that particles, which gain heat energy, move more quickly. In our case the reacting particles are the substrate (hydrogen peroxide) and the enzyme catalase. As the temperature is increased the particles of hydrogen peroxide have more energy therefore they collide with the potato more frequently and so increasing the rate at which the product is formed. However at a certain temperature this is no longer the case. This is because enzymes are proteins and proteins can be denatured at high temperatures. This is because proteins have a 3D shape. In our case the catalase has a certain shape that the substrate fits into. At high temperatures the active site on the enzyme is altered, see diagram below. (Diagram showing active site on the enzyme is altered therefore stopping products being formed) This stops the substrate from ‘fitting´ and so no product is formed. My results do not totally support or undermine my origin...