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effect of different concentration of H2O2

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The aim of this investigation is to find out if changing the substrate concentration will have any effect on the activity of the enzyme activity. Enzymes are a very important for all living things. This is because they are essential to life as they are used in virtually every metabolic reaction. They are designed to work within a temperature range of 5-40�C, they do this as if it was any higher it would damage living cells. We call an enzyme a Biological Catalyst. A catalyst is a molecule which speeds up a reaction. They are very important as if they were not there reactions in cells would be to slow to support life. They speed up reactions by lowering the activation energy needed in the reaction. The activation energy is the energy needed to get a reaction going e.g. activation energy is like pushing a rock to the top of a hill and then pushing it off the top. The activation energy is the energy needed to get the rock to the top of the hill. When it is pushed of the top it no longer needs any help and it does it by itself. The diagram below explains activation energy: - Activation energy graph without enzyme Activation energy graph with enzyme There are two types of enzyme reaction, these are: - * Anabolic - involved in synthesis * Catabolic - involved in breakdown (yeast and hydrogen peroxide is this type of reaction) One amazing thing about an enzyme is that when it is used in a reaction it will come out after the reaction exactly the same it was when it went in. All enzymes are globular proteins but not all globular proteins are enzymes. They have a three dimensional structure with hydrophilic R-groups arranged on the outside to ensure that the molecule is soluble. Enzymes are specific, this means that each enzyme will only work with one reaction or one small group of reactions. ...read more.


The 10% concentration of the hydrogen peroxide (substrate) was made by diluting the 20% hydrogen peroxide by added water to it i.e. adding 50 cm3 hydrogen peroxide to 50 cm3 of water. Table to show results for test 3 of the preliminary study Concentration (%) Substrate Volume (cm3) Water (cm3) Yeast Volume (cm3) 10 20 0 2 8 16 4 2 6 12 8 2 4 8 12 2 2 4 16 2 Table 3 Results to test 3 This change to quantity's worked well with the gas syringe taking the oxygen given off in the first 180sec in its measured space. Bibliography Web Sites used An explanation for the shape of the enzyme kinetics curve - www.biology.arizona.edu Information on catalase - www.hamline.edu Books used Cambridge Advanced Sciences - Biology 1 Biological Sciences 1&2 Implementing Safety issues When working with chemical of any kind care has to be taken to ensure there are no accidents occur. This means you must implement safety procedures. The safety procedures which will be adopted when implementing the experiment: - * Wear safety glasses to protect eyes from splashes of hydrogen peroxide * All round care needs to be taken to avoid breakages of glass * When throwing away chemical ensure they are thrown away correctly i.e. into a basin in a sink not in a bin or down the drain * When clearly up breakages do not throw broken glass straight into bin. They have to be disposed correctly i.e. wrapped in paper of disposed in a bin dedicated to glass. Risk Assessment Risk Chance of occurrence of risk (1-5) Severity of risk (1-5) Total Score (out of 25) RISK FACTOR Precautions Splashes From Hydrogen Peroxide 4 2 8 Wear Safety Glasses to protect eyes Spillages 2 2 4 Be careful not to spill solution and if there are any spillages clear up immediately. Injuries from broken Glass 3 1 3 Clear up the glass following the procedures above. ...read more.


This will prevent mix up and allow results to be more accurate. Accuracy The accuracy in this investigation was poor. This is because the operator did not record the results well as they misread the gas syringe on a number of occasions which led to anomalous results. This has to be improved in any future experiment. This could be done by always double checking the results to ensure they are correct. The accuracy of the Gas Syringe was not very good as it could only be accurate to whole numbers. It have done with being accurate to one decimal place so that the results could have been more accurate as with no decimal place is up to the operator to decide what the result is. The reliability of the other pieces of the apparatus was good and could not be improved. Reliability This investigation could have been more reliable but it was limited to the resources of the school. This meant that only two sets of results could have been taken. This reduced the reliability of the investigation because the averages of two sets of results are not as good as three sets. If the investigation was done again a minimum of 3 set would be taken. This would increase reliability of the results. This would allow the results to be more valued so the analysis could be proven. Overall this investigation has gone well. The results would have been better if 3 sets had been taken by the schools resources limited it to only two. If the investigation was done again then the improvements which were mentioned above would be implemented. This would improve the overall results and make it the whole investigation more reliable. ?? ?? ?? ?? This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ Yeshak dejene This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ This document was downloaded from Coursework.Info - The UK's Coursework Database - http://www.coursework.info/ ...read more.

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