Apparatus: Two test tubes, mat, measuring cylinder, starch solution, amylase solution, spotting tile, pipette, stirring rod, stop clock, beaker, gauze, tripod, Bunsen burner, thermometer, water and ice cubes.
Safety: You will need goggles when you will be heating chemicals, gloves when you will be touching dangerous chemicals and tongs to pick hot objects.
Fair test: To make sure that this experiment is a fair test, I must only vary the temperature, so this means that I have to keep everything else exact. I will use accurate equipment and time.
Variables: I have chosen to repeat my experiment twice, because it therefore gives me accurate results. I will use accurate measurements, and accurate equipments to make this experiment fair.
Method:
The aim of this experiment is to find the appropriate temperature for the enzyme amylase to work. I did this by firstly setting up the equipment. Next, into a test tube I measured 1cm3 of amylase solution and into to the second test tube 4cm3 of starch solution. I also squeezed few drops of iodine solution into each well of the spotting tile. The temperature of my water will be 10c, in order to get the water to that temperature I added ice cubes to the 100ml beaker full of water. When it had reached that certain temperature, I placed both test tubes in the beaker full of ice and water, and then I added the thermometer. Then soon afterwards I mixed the test tubes together so the enzyme amylase can breakdown starch and I started the stop clock. I timed it until the mixture was not a blue/black colour, because this is the colour to detect starch in the solution. After every 30 seconds, we took 1 drop of starch/amylase mixture and added it to the first dimple in the tile. The colour was still blue/black; this meant that starch was still present and that I needed to time it for longer. By doing this it will tell me how fast the enzyme worked at this temperature. I recorded the colour and time into my result table. When the clock read another 30 seconds, I took another drop of the mixture and added it to the second dimple of the tile. The colour was still blue/black. I recorded the colour of the iodine solution into my table. I repeated this procedure until there was no starch left. After I had completed the first temperature, I continued to do the rest of the temperatures, which were 20c, 30c, 40c, 50c, 60c and 70c. For these temperatures, we heated the water up to the certain temperature by using a Bunsen burner, and continued the experiment as usual. In doing this I am seeing how fast the enzyme worked and how each temperature affected its performance. To make this a fair test I will keep everything in this experiment same accept the temperatures.
Table of results:
Conclusion:
Several details can be seen from the results of this experiment. Firstly, I believe that the graph is very similar to my prediction.. It shows an optimum temperature at which the enzyme worked well. It also shows a pattern that the higher the temperature the better the enzyme worked, although the enzyme did not work well at a too high temperature. You can tell this from my graph because at 60 to 70c the line of best was stationary, in other words it did not move, this is because the enzyme did not work well at a very high temperature as the enzyme denaturized. The enzyme worked well around 35 to 45c where the line of best fit was at an average pace because the enzyme was not too hot. Also the enzyme did not work well at 10c because the temperature was too cold. When the temperatures increases the particles move faster and there is more chance of collisions. At low temperatures particles to not have enough energy to collide so reaction takes time to take place.
When starch was present, the iodine turned blue/black. As you can see from my table of results that at 10c starch was present for 407 sec this tells you that the enzyme took quite a long time to breakdown the starch as the enzyme does not work at low temperatures. Although at 50c it took 169sec for the starch to breakdown this shows that starch was present for a little time until it was broken down, so the enzyme worked well at this optimum temperature. At 70c the colour of starch amylase was orangey this tells you that there was no enzyme there to breakdown starch and that he enzyme had denaturized. My results prove that my prediction was right because I said that the breakdown of starch by the enzyme amylase will be rapid and will increase as the temperature increases.
Evaluation: My results proved my prediction to be correct. The breakdown of starch was quicker as the temperature increases until the optimum temperature, and then it begins to slow down. I think my results were acceptable to conclude firm conclusion. The information obtained in this experiment was fairly accurate as my graph shows although there were some inaccuracies during the experiment, which I would like to share. I found it difficult to measure accurately the two solutions, too much noise in class interrupted my concentration, I failed to wash both test tubes when I carried out the next experiment and sometimes I did not have an accurate time on the stop clock as I was interrupted by other members in class. I made this a fait test by repeating the experiment, so we obtained I could have accurate results. The experiment was a success but I think I could make further improvements if I carried the experiment the third time, so I could compare the two results and have an average result. If I had to carry out the experiment again I would use accurate electronic equipment and conduct my experiment in a quiet place. To extend this investigation I would probably use another enzyme and see if they both follow the same rule.
