For this investigation I am going to investigate the effect of the concentration of an enzyme, in this case amylase, on the time taken for the enzyme to fully breakdown the substrate, which in this case is starch.
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PLANNING For this investigation I am going to investigate the effect of the concentration of an enzyme, in this case amylase, on the time taken for the enzyme to fully breakdown the substrate, which in this case is starch. The reason why these two substances have to be used is because each enzyme is designed specifically to break down only one substrate as each enzyme is made of a protein that causes it to be a specific shape, in this case the enzyme amylase can only break down starch to dextrin. I am going to do this by planning an experiment, carrying out the experiment, recording any relevant results and plotting graphs from which I will be able, to gain a strong conclusion. I will finally evaluate the whole investigation. Before the experiments start we will be given a bottle containing a 1% suspension of starch and another bottle containing a 1% solution of the enzyme amylase. From these bottles I will be able to take out as much of either solution as I wish. I cannot start the experiment until I know which factors I am going to change and which I am going to keep constant. Because the variable I am trying to test is the effect of the concentration of the enzyme, the only thing that I should be changing in each experiment is the concentration of the enzyme and nothing else. This will make all of the tests identical (apart from the enzymes concentration) which means the experiment should be accurate and fair. Because of this any differences in the results of my experiment I will be able to put down to the concentration of the enzyme.
Additionally, to overcome an obstacle I had to dilute the starch, too in order to maintain the accuracy. For instance, we had 10 cm3 volume of starch but to dilute it down to 1%, I mixed 5.0cm3 starch and another 5.0 cm3 of water in to a test tube, therefore, we could add the percentage of the concentration of the starch up to 1. 15 x 10mm diameter test tubes : These will be used for diluting the solutions and for Clean test tubes mixing the amylase with the starch in the water bath. The test tubes have to be clean to prevent any unwanted contaminants getting into the experiment. 3 x 10ml syringe : Used for very accurate measuring of both the amylase, starch solution and water. This will be vital for getting the correct volume of the 3 substances into the test tubes. Thermometer : The most accurate way of measuring the temperature of the water bath and therefore the temperature of the enzyme and substrate. Stopwatch : To measure accurately the time it takes for each to 10th of a second concentration of amylase to break down the starch. 250cm3 : for the water bath because it is large enough to hold the water, 2 test tubes and the thermometer at the same time. It also conducts heat well. Bunsen burner Heat Proof mat, tripod Test tube rack : To hold the test tubes before and after the reaction has Tongues been carried out. Iodine solution : To test for the starch as iodine turns from a reddish orange color to purple- black if starch is present (with dropper.) Pipette : to take a tiny volume of the solution out of the test tube during the time when the enzyme will be breaking down the starch.
Because they get faster and quicker. Predicted observations and graph The graph I will be plotting will be of concentration of amylase against time taken for the starch to be broken down. I believe that the graph will show that as the enzyme concentration increases the time taken decreases. I predict that the rate of reaction will increase as the temperature increases (having a positive correlation) until the reaction reaches an optimum temperature. Above this optimum temperature, the rate of reaction will fall to zero very quickly as the enzyme denatures. The breakdown of starch will be quicker when the temperature is increased until it exceeds 40° C. Then the amylase will no longer catalyze the breakdown of starch. Above, I indicated an example Exponential Decay Curve so that after every x minutes, the starch concentration would half and would therefore never be totally broken down. It was predicted that, if a graph were drawn to show starch concentration against time, it would be an exponential decay curve. The exponential behavior was predicted because the reaction is not an equilibrium reaction: as the starch concentration decreases the enzyme finds it increasingly difficult to find enough substrate to act on. Although using iodine to test for starch would prevent a graph from being drawn in this way, the trend would still be evident. Furthermore, I have to conclude from the graph I will draw in the following page, that 1.00% concentration is the maximum in other words, the highest it can reach. ANALYZING EVIDENCE Concentration of amylase/ % Time taken to digest starch s 1.00 0.00 0.80 1.00 0.67 1.50 0.50 3.00 0.25 4.00 Here are the readings of my data. Now, I should try plotting a scatter graph using these readings. Therefore, analyzing the hypothesis will be much more clear and precise to see according to the anomalous results omitted.
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