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This is an experiment to show how different concentration of celery tissue enzyme, catalase breakdown the bonds of hydrogen peroxide, substrate, to produce oxygen given out at different rate of reactions.

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Introduction

Aim: - This is an experiment to show how different concentration of celery tissue enzyme, catalase breakdown the bonds of hydrogen peroxide, substrate, to produce oxygen given out at different rate of reactions. Planning Background research:- Catalyst: Catalyst is a substance that speeds up the chemical reactions, without it self being consumed by the process. Any such process is called catalysis. In industries, catalysts are used to speed up many chemical reactions that otherwise will take place too slowly to be practical. Enzymes: Enzymes are proteins. Like other proteins, enzymes consist of long chains of amino acids held together by peptide bonds. Enzymes take part in the breakdown of food materials into simpler compounds. They are also called biological catalyst. This means that by their mere presence, and without being consumed in the process, enzymes can speed up chemical processes that would otherwise run very slowly, if at all. Enzymes are normally named after the reactions they catalyse because their molecular structure is very complex and in many cases unknown. For example, super oxide dismutase is the enzyme responsible for the destruction of the super oxide ion in living organisms. Enzymes are specific. Contrary to inorganic catalysts such as acids, bases, metals and metal oxides, enzymes are very specific. In other words, each enzyme can break down or synthesize one particular compound. In some cases, they limit their action to specific bonds in the compounds with which they react. Most proteases, for instance, can break down several types of protein, but in each protein molecule only certain bonds will be cleaved depending on which enzyme is used. Enzyme Mechanism: One of the unique things about enzymes is that they have one function and one function only. This is to reduce the activation energy. Every substrate in an organism has its own unique enzyme. The substrate, which is to be transformed, fits the enzyme like a key in a lock. ...read more.

Middle

It will produce bias results between the concentrations. Apparatus I will be using the same apparatus for each experiment. If I have the same apparatus the experiment will be same. Further more, it will rule out any chance of it being an unfair test. The one variable that will change Enzyme concentration: Enzyme concentration greatly affects the rate of reaction and is the only variable I will be changing in my experiment. It's so because I want to measure the rate of reaction i.e. the oxygen produced in different enzyme concentrations. To change the enzyme concentration I will dilute it with distilled water. This will give different concentrations of enzyme. This is the way we make different concentrations of enzymes. 10cm3 = 100% concentration 8cm3 + 2cm3 = 80% concentration 6cm3 + 4cm3 = 60% concentration 4cm3 + 6cm3 = 40% concentration 2cm3 + 8cm3 = 20% concentration My hypothesis for this is the more the concentration of enzyme, the more rate of reaction, as with more enzymes we will also have more active sites available to catalyse the substrate, hydrogen peroxide. As we lower the enzyme concentration the rate of reaction will also decrease, as there are only a restricted amount of active sites. . So, although there will be collision occurring between enzyme catalyse, and substrate hydrogen peroxide but very low reaction will occur as enzyme molecule is already occupied by another hydrogen peroxide, as a result of this the rate of reaction will be lower and the amount of oxygen produced will be less. Implementing Results The results of experiment 1 and 2 are given below and so are the concentrations. Experiment 1 100% Oxygen collected (cm3) Time(s) 1 2 3 Average 0 0 0 0 0.0 10 16 17 22 18.30 20 24 30 29 27.6 30 32 37 43 37.3 40 43 45 47 45.0 50 50 48 55 51.0 60 52 57 63 57.3 70 59 63 67 63.0 80 62 66 66 64.6 90 65 64 74 ...read more.

Conclusion

This is because the values for each experiment over the amount of oxygen were not so spread out. Also as the experiment was repeated twice it cut down quite a lot of anomalous results. I also calculated average; it should have improved the accuracy. The results I got were also fairly accurate. This is because they were as I was expecting them to be. All the repetitions were closed to each other and this strengthened my overall end results. This gave me the line of best fit in my graphs. Precision is a component of accuracy, but it is not the same as accuracy. It can be seen in the equipments I used. This can again be seen in the concentration of enzyme concentration as I have explained above. I have listed my limitations and errors and how I could overcome them. My conclusion does agree with my hypothesis in that, the amount oxygen as well as the initial rate of reaction increases, as the rate of reaction gets higher. On the whole my experiment is a well-grounded success, in spite of all the errors and restrictions. References Collins Advanced Science _ Kathryn Senior and Mike Boyle Comprehensive Biology _ Lam Peny Kwan Biology 1 _ Mary Jones, Richard Fosbery and Dennis Taylor New Understanding Biology _ Glenn and Susan Toole Class Notes Advanced Biology _ Michael Kent www.google.co.uk Content page 1. Front Page 2. Content Page 3. Aim and background knowledge 4. Background knowledge 5. Background knowledge 6. Background Knowledge 7. Background knowledge 8. Background knowledge, prediction 9. Prediction 10. Apparatus 11. Apparatus 12. Diagram 13. Methodology 14. Risk assessment and the variables I will control 15. The variables I will control and the variable I will be changing 16. Result 17. Result 18. Result 19. Result 20. Result 21. Graph figure 1 22. Graph figure 2 23. Analysis of results 24. Analysis of results 25. Graph Figure 3 26. Graph Figure 4 27. Analysis of graph 28. Graph figure 5 29. Graph Figure 6 30. Analysis of graph 31. Ratings 32. Ratings 33. ...read more.

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