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Enzymes - investigate the affect of amylase concentration on starch breakdown into glucose.

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AIM The aim of this investigation is to investigate the affect of amylase concentration on starch breakdown into glucose. To do this a couple of variable should be brought into consideration. They are the amount of amylase and the time taken for the starch to break down into glucose. PREDICTION I predict that if I increase the concentration of amylase in the starch then the amount of time taken for the starch to break down into glucose will decrease, hence making it's rate of reaction higher. This is because there will be more active sites for reactions, resulting in more chemical reactions caused by successful collisions between the active site of the amylase and the starch. The higher the concentration of amylase in the starch then the amount of time taken for the starch to break down into glucose will decrease. This is because there is more amylase in a higher concentration gradient to break down the starch into glucose, thus making the reaction time much less. However there is less amylase in a lower concentration gradient that makes the reaction time longer because there is not enough amylase to break down he starch in one go. Enzymes are biological catalysts/scissors. They speed up reactions within the body so that they can take place at body temperature. The enzyme is not used up in the reaction and can continue work on other substrate molecules. Enzymes are proteins with a special shape. All enzymes are made up of hundreds of amino acids joined together in a specific way. The protein (enzyme) molecule becomes twisted to form a special 3 dimensional shape, which can combine with a reactant (substrate) molecule, like a fitting in a particular key. Enzymes combine with reactants, called the substrate. The enzyme allows the products to form the substrate by making and breaking chemical bonds easily. An enzyme molecule can bring about hundreds of changes like this each second. ...read more.


Then I will stop the stopwatch as soon as the substances in the test tube turn colourless. SAFETY In order to conduct a safe experiment, I will follow all the lab rules of the classroom and will behave in a respective and mature manner. I will not do anything dangerous that would put any fellow classmates at risk. I will wear safety goggles and will clear my work area of any unnecessary equipment. APPARATUS I will make this experiment safe by following the lab instructions of the classroom. APPARATUS # MEASUREMENT USE Amylase - 100 ml For the Experiment Starch - 100 ml For the Experiment Water - 100 ml To dilute amylase and for the water bath Kettle 1 - To boil water for water bath Stopwatch 1 - To time reaction Pipettes 3 3 ml To measure accurate amounts of water, amylase and starch Test Tube 1 - For the reaction to take place in Measuring Cylinders 2 10 ml To measure the amount of starch and amylase Beaker 1 100 ml For the water bath Iodine 1 100 ml To see whether starch is present or not Thermometer 1 - To measure the temperature of the water bath Beaker 1 10 ml To mix the amylase and water to from a concentrated solution Safety Goggles 1 - For the protection of your eyes Test tube rack 1 - To put the test tube on when not in use. METHOD 1. Pour 5 ml of starch into the measuring cylinder. 2. Use one Pipette to make sure that you have measured exactly 5 ml. 3. Pour that into a test tube. 4. Put the test tube into the test tube rack. 5. Heat water in a kettle. 6. Pour 100 ml of boiling water into a beaker to create a water bath. 7. Put the thermometer in the water bath. 8. Add a sufficient amount of cold water into the water bath so that the temperature of the water bath is at 40�C. ...read more.


Most of my results were accurate, however some were not because they were anomalous results and did not follow the trend. If I could do the experiment again, I would improve it by trying to cut out human error. By this I mean that would be more careful whist measuring and would also be quicker in starting the stopwatch. If I were to do the experiment again I would prefer to use a different method such as the method I suggested earlier, a computerised method rather than using this same method again because the computerised method is more accurate and has less of a margin of human error. However the method I used can produce very inaccurate results if I was not careful in measuring and also has a larger margin for human error. Another alternative method is to use a colorimeter to measure the colour of the amylase, starch and iodine solution, to see when the solution has turned colourless. By using this method you are able to cut out all human error when it comes to measuring the colour of the solution. I could also use a syringe to measure the volume of the liquids before pouring them into the test tube instead of a measuring cylinder. A syringe has smaller scale divisions, of which the thickness of the line is even very small. A measuring cylinders division are large and the thickness of the line on it is quite thick. This would enable be to be more accurate. RESULTS RELIABILITY I believe that my results are reliable and sufficient because all the points are on a straight line, the tests covered enough range to show the full shape of the graph, as a result I am certain that I have got enough results to be sure about my conclusion as being correct, acceptable. Here is a graph to show the reliability of my results: - The error bars in red on the y-axis show the percentage error of 10 for the time taken for each concentration gradient. ...read more.

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