An Investigation Into The Factors Affecting The

Activity Of The Enzyme Essay, Research Paper

Amylase – Planning *Hypothesis I predict that as the temperature increases, the speed of the reaction will increase. When a particular temperature is reached I believe the rate of reaction will dramatically decrease. I believe this because most chemical reaction happens faster when the temperature is higher. At higher temperatures molecules mover around faster, which makes it easier for them to react together. Usually, a rise of 10OC will double the rate of reaction. This is true for enzymes up to about 40OC. However at 40OC the enzyme begins to be damaged, so the reaction slows down. By 60OC the enzyme is completely denatured. I predict that the same will happen the further away the pH is from pH 7. I believe this because the optimum temperature for most enzymes is about pH 7 therefore the further away from pH 7 (either more alkaline or more acidic) the less affective the enzyme. *Pilot Experiment To investigate the factors affecting the activity of the enzyme Amylase, I will adapt a pilot experiment, which investigates if the enzyme amylase breaks down starch. The pilot experiment was: *Pour amylase solution into a test tube to a depth of 2cm. *Half fill another test tube with a 4% starch solution. *With a pipette place a drop of iodine into each dimple in a dimple tray. *With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control. *Rinse the glass rod. *Pour amylase solution into the test tube of starch and shake quickly. *Repeat steps 4 & 5 (for the amylase & starch solution mixture) every 30 seconds until a blue/black colour no longer develops. *When there is no further change in the colour of the iodine, take the starch-amylase test tube, add Benedict’s reagent, and place in the water bath for 1 minute. *Adapted Experiment I will modify and expand the pilot experiment in a number of ways. Firstly I must decide what I’m going to investigate. I am going to investigate the effect of pH and temperature on the activity of the enzyme amylase. Therefore I have developed two similar experiments (one for each factor I’m investigating). To investigate the effect of pH on the activity of the enzyme amylase: *Pour amylase solution into a test tube to a depth of 2cm. *Half fill another test tube with a 4% starch solution. *With a pipette place a drop of iodine into each dimple in a dimple tray. *With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control. *Rinse the glass rod. *Add 2cm3 of the appropriate pH buffer to the starch solution and shake. *Pour amylase solution into the test tube of starch and shake quickly. *Repeat steps 4 & 5 (for the amylase, starch & pH buffer mixture) every 30 seconds until a blue/black colour no longer develops. *Record the results in a table. Repeat steps 1-8 for each pH buffer range until all the provided pH buffers have been used. To investigate the effect of temperature on the activity of the enzyme amylase: *Pour amylase solution into a test tube to a depth of 2cm. *Half fill another test tube with a 4% starch solution. *Cool both test tubes and maintain at 10OC *With a pipette place a drop of iodine into each dimple in a dimple tray. *With a glass rod lift a drop of the starch solution from the test tube and mix it with the first drop of iodine in the first dimple in the tray. A blue/black colour should develop; this will be used as the control. *Rinse the glass rod. *Add 2cm3 of water to starch solution (see below). *Pour amylase solution into the test tube of starch and shake quickly (measure temperature, try to maintain at 10OC). *Repeat steps 4 & 5 (for the amylase & starch solution mixture) every 30 seconds until a blue/black colour no longer develops. *Record the results in a table. Repeat steps 1-9 increasing the temperature by 5OC each time until the enzyme is denatured, this should be around 40OC (see part 6 on enzymes.) To ensure that the test is fair I will only vary two factors (at different stages of the experiment not simultaneously). All the quantities will have to be carefully measured since small variations in the amount of enzyme used can make significant variations in the results. In the section where temperature is investigated, 2cm3 of water is added. This is because the starch solution is neutral and in the previous investigation (for pH) 2cm3 of the appropriate buffer was added. If the 2cm3 of water was not added then it would not be a fair test since the volumes used in each part of the investigation would be different. If they were different then this would affect the results since the solution would be of different concentrations and therefore one would react faster than the other would. *Apparatus I have chosen to use a measuring cylinder to measure the volumes of substances used since it is more accurate than a pipette. I will use an electronic water bath for maintaining the mixture at a temperature above room temperature since the temperature is more accurate than a water bath above a Bunsen burner. I will have to use ice from the freezer to reduce the temperature of the mixture to 10OC. A 100OC thermometer will provide temperature results of a sufficien