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The Effect of pH on Catalase
- Essay length: 3649 words
- Submitted: 11/07/2002
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Marked by teacher:
Luke Smithen
Teacher essay summary
This is a very good report on a practical that demonstrates a good understanding of scientific processes.
1. The background knowledge is good but needs referencing.
2. The preliminary test is also good. However, the conclusion from it needs to be readdressed.
3. The language used is appropriate throughout
4. The conclusion section has become confused about the information that should be included.
5. The evaluation is thoughtful and detailed.
**** (4 stars)
Marked by teacher Luke Smithen 01/05/2013
The first 200 words of this essay...
The Effect of pH on Catalase
Hypothesis: The rate at which catalase catalyses the decomposition of hydrogen peroxide increases to an optimum pH and then decreases as the optimum pH is exceeded.
Biological knowledge:
Hydrogen peroxide is produced in plant and animal cells as a by-product, which is toxic, resulting in the need of catalase to speed up the decomposition of hydrogen peroxide to water and oxygen. All microbodies contain catalase and it is the fastest known enzyme with a turnover number of 6 million. It is especially abundant in plant storage organs and in liver. It is effective over the pH range of 4.0 to 9.0 with the optimum pH of 7.6.
2H2O2(aq) catalase 2H2O(l) + O2(g)
As an enzyme, its rate is affected by various factors, including pH. Changes in pH alter the ionic charge of acidic and basic groups of the enzyme. This therefore distorts the shape of the enzyme, including its active site, where substrates temporarily bind. The efficiency of forming enzyme-substrate complexes is consequently lowered and the rate of activity decreases. However, the enzyme can regain its most proficient shape, if it is not exposed to too extreme
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MbT essay summary
This is a very good report on a practical that demonstrates a good understanding of scientific processes.
1. The background knowledge is good but needs referencing.
2. The preliminary test is also good. However, the conclusion from it needs to be readdressed.
3. The language used is appropriate throughout
4. The conclusion section has become confused about the information that should be included.
5. The evaluation is thoughtful and detailed.
**** (4 stars)
