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Investigate the effect of the concentration of catalase on the rate of decomposition of hydrogen peroxide

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Biology Coursework: Investigate the effect of the concentration of catalase on the rate of decomposition of hydrogen peroxide Zahra Khan: - 12WS Centre number: - 51619 Candidate number: - 6547 Introduction For this investigation I have been asked to investigate (by experimentation) the effect of substrate concentrations on the rate of the decomposition of hydrogen peroxide when catalyzed by the enzyme catalase. This is part of our work on the function of enzymes, how they work and the effects of conditions on how they work. We have learnt about the formation of enzyme-substrate complexes, the lock and key model, induced fit model, activation energies of normal reactions and enzyme-catalyzed reactions, equilibrium, specificity and denaturisation. An enzyme (Catalase) is a biological catalyst. It can modify the rate of reaction without being changed itself. Enzymes are also globular proteins that have a three-dimensional specific shape; among with a pocket known as the active site, this has a precise shape to link with the exact substrate. Every enzyme is capable of converting one kind of substrate molecule into one kind of product molecule, which forms the enzyme-substrate complex. However these are the minority factors that can affect the rate of reaction: Temperature: If the temperature was to increase so would the rate of reaction up to a decisive point, as the enzyme will start to denature; this usually occurs at temperatures around 50 to 60 Celsius. The rate of reaction increases because enzymes and substrate have more energy permitting them to move around more rapidly, resulting with more collisions and ensuring the enzyme-substrate complex. ...read more.


These are the variables which may affect my results: Variables How it will be controlled? Why it needs to be controlled? Concentration Decide how much water to add The point of the procedure is to see how different levels will affect the rate of reaction. Temperature The experiment will be conducted on the same day in the same place in a short period of time. As temperature increases rate of reaction increases up to the optimum temperature. If the temperature gets too hot the enzyme becomes denatured and reaction stops. Volume Measure out same volume of hydrogen peroxide every time To see how each level of hydrogen peroxide Safety measures: Safety precautions are a serious matter to the practical as a whole and not carrying out any precautions cause danger to me as well as those around me. The following is a list of the procedures that I will take out: 1. Wearing appropriate goggles, apron and safety gloves 2. Work in centre of table with plenty of space. 3. When using hydrogen peroxide there are many factors that need to be taken into consideration because it is corrosive and causes burns. It is also irritant to the eyes and skin. It's a dangerous product and can cause explosive reactions and causes internal damage if swallowed due to release of oxygen. 4. Work standing up and with chairs under tables and not in the way. Method Water (h20) ...read more.


This transaction was done as concurrently as rationally possible, but there was certainly some delay, so a little gas would have been lost; also gas could have been lost at other connections. This would have slightly affected the results. The fact that I may also have delayed in stopping the stopwatch or may have stopped it too early could also have effected the readings also considering the fact that readings were taken by eye, and although they were taken by looking at the scale as near to right angles as possible, there may well have been possible errors. I did not monitor any changes in the temperature of the hydrogen peroxide and this may have altered my results slightly, this was very hard to control because we had a rubber bung at the end of the test tube, so there was no where for a thermometer to go. I could have controlled the temperature of the hydrogen peroxide better by putting it in a water bath, to try and keep the temperature more constant. Evaluation The procedure of this experiment could be improved, although the results do give an adequate conclusion. Improvements would simply remove certain errors, and improve the accuracy of results. Using slightly different procedures could reduce the delay between putting in the hydrogen peroxide and replacing the bung and starting the stopwatch. The best solution would be to find a method that doesn't require the bung to be removed and replaced each time. ?? ?? ?? ?? Zahra Khan- Biology coursework ...read more.

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