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Enzymes Investigation

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Planning What am I trying to find out I 'am trying to find out what the optimum temperature for the enzyme 'catalase' (which is in the liver) is in breaking down Hydrogen Peroxide (2H2O2) into water and oxygen (2H2O + O2) this process is called decomposition. I will also try to find out the volume of oxygen that there will be in thirty seconds. What are Enzymes? The chemical reactions of metabolism would go very slowly or not at all, if it were not for enzymes, enzymes are large proteins that speed up chemical reactions inside a cell, but the enzyme itself is not used up in the reaction this allows the enzyme to do the same thing over and over again. In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. The enzyme itself is unaffected by the reaction. ...read more.


The only thing that will be different is the temperature, which will range from 0?C to 80?C, this is how I will find the volume of oxygen. The Method At first I used a scalpel to cut a small piece of liver, I then measured it to about 0.9g, I made sure this was accurate and I thought I should use the same piece of liver during the whole experiment. This is because the surface of different size pieces of liver has different sized active sites. After measuring and cutting the liver I measured out 3ml of Hydrogen Peroxide, I then poured it into a small test tube and so I had it ready to be poured into the test tube containing the liver. I put both test tubes in a water bath to reach the temperature before adding them together. Next I placed the liver into the test tube and placed the test tube into the beaker. Then I connected the tubes leading from the bong into the other beaker, which was full of water. Next I filled the measuring cylinder with water and placed it above the tube. After the set up was done I quickly poured the Hydrogen Peroxide (3ml) ...read more.


I think that overall my original prediction does support my conclusion. Evaluation Was it a fair test? In my opinion I think that the experiment was not very reliable or fair, this is because the timing used was unreliable and that the amounts and surface area's were not reliable. Also the temperatures, which were a big part in the experiment, were not always exact, this can cause a lot of problems to do with the experiment as difference in the temperature of the water can cause inaccuracies in the measurement of oxygen produced Were their any anomalies? In this experiment there weren't any anomalies this was because I would retest any odd results that I would have, this would make the test fairer. Was the method reliable? I think, although the units were not always precise the set up and method were both accurate. This because the results were all in a suitable range and that they weren't anomalous temperatures Improvements There are a lot of improvements in my mind that could be done about the experiment for example: * Tests should have been repeated and considered which would be more accurate. * The amounts of liver, Hydrogen Peroxide, water and temperature should have also been considered. * The timing of the reactions (30 seconds) could have been increased or decreased depending on the activity of the reactants. ...read more.

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