An Enzyme Controlled Reaction-Catalase - Essay Example

An Enzyme Controlled Reaction-Catalase 1.0 AIM: To study the rate at which catalase produces oxygen in various concentrations of hydrogen peroxide, using a pureed potato. 2.0 HYPOTHESIS: The rate of reaction is high at low concentrations of hydrogen peroxide, but this rate will reduce as the concentration is increased. When the reaction attains saturation, the reaction will cease to take place. The rate of reaction is expected to increase because more substrates are getting an opportunity to react with more active regions of the enzyme as concentration of H2O2 is increased. 3.0 EQUIPMENT: Figure 1: Arrangement of the apparatus for the experiment LIST OF EQUIPMENT: 1. Hydrogen peroxide 2. Pureed potato 3. Beaker 4. 2 cm3 Syringe 5. Rubber bung, 2-holed 6. 100 cm3 conical flasks 7. Delivery tube 8. Pneumatic trough 9. 50 cm rubber tubing 10. 100 cm3, 50 cm3 measuring cylinders 11. 2 clamp stand, clamp and boss 12. Stopwatch 4.0 Methodology The following procedures are followed in conducting the experiment: a. Prepare adequate diluted hydrogen peroxide. b. Prepare enough pureed potato fresh c. As shown in the arrangement of apparatus in figure 1, make up 2-holed bungs. d. Pour 20 cm3 of pureed potato into the conical flask using the large syringe. e. Put the bung, carefully, in the flask f. Half-fill the trough with water g. Add water to the 50cm3 cylinder, and then turn it upside down over the trough of water, and clamp it in place. h. Put 2 cm3 of hydrogen peroxide through the bung of the flask, without pushing the plunger promptly. i. Ensure that the rubber tube is fixed well in the measuring cylinder. Start the stop clock immediately after pushing the plunger on the syringe. j. The volume of oxygen is then noted after 30 minutes and the results put in an appropriate table. k. Clear the conical flask and fill it with another 20 cm3 pureed potato. Repeat the procedures from g to j, but this time round with a different concentration of H2O2. l. Compute the rate of O2 production (cm3/s). m. Plot a graph of concentration of hydrogen peroxide against rate of oxygen production. 5.0 Safety Measures Hydrogen peroxide in high concentrations (18-28 vol.) is irritating to the eye and the skin. The contaminants can cause decomposition leading to explosion after a while. Pressure can build up if reaction containers are blocked. 6.0 Results This experiment has 1 independent variable, 1 dependent variable and 1 control variable. The independent variable is the various concentrations of hydrogen peroxide, while the dependent variable is the rate of reaction in terms of oxygen production. The control variable is the temperature of the room and standard pressure. Table 1 shows the average results of the oxygen produced in different concentrations of hydrogen peroxide. Percentage of Hydrogen peroxide Average volume of oxygen collected (cm3) over time (seconds) 5 10 15 20 25 30 35 40 45 50 55 60 100 48.3 68.7 78.3 82.0 85.0 86.7 87.0 87.3 87.7 88.3 88.3 88.3 90 37.3 55.0 63.7 68.3 71.0 72.3 73.0 73.3 73.3 73.3 73.3 73.3 80 32.3 47.3 54.0 59.0 61.3 63.0 63.3 63.7 63.7 63.7 63.7 63.7 70 26.3 40.0 45.7 48.3 49.0 49.3 49.3 49.3 49.3 49.3 49.3 49.3 60 20.7 31.7 36.7 40.0 42.7 44.0 44.7 44.7 44.7 44.7 44.7 44.7 50 16.3 27.0 31.0 33.3 35.3 36.3 37.0 37.0 37.0 37.0 37.0 37.0 Table 1: Average volume of oxygen collected Figure 2: reaction at 100% concentration of hydrogen peroxide Figure 3: reaction at 80% concentration of hydrogen peroxide Figure 3: reaction at 50% concentration of hydrogen peroxide 7.0 Discussion To ensure that the process of measuring was accurate, I ensured the room temperature remained constant and the equipment remained in the same conditions for all the tests. In some tests, the level of concentration of hydrogen peroxide was not very accurate due to some technical hitches, but the level of inaccuracy was not substantial enough to affect the findings and conclusion of the experiment. From the results, it appears that less oxygen was produced within the first 5 seconds because the concentration was low. This is because, at higher concentrations of hydrogen peroxide, there are more molecules of hydrogen peroxide leading to more collisions that stimulates more enzyme-substrate to be formed – as the concentration decreased, this collision decelerated as evidenced by the graphs (Chelikani, Fita & Loewen, 2004). These results are exactly as it was expected. Catalase functions as catalyses in most living organisms, by decomposing hydrogen peroxide into oxygen and water, as shown in the equation below. 2H2O2 + Catalase 2H2O + O2 Catalase significantly trims down the activation power required for the reaction. In absence of catalase, the breakdown would take a longer time to occur, and would not be able to support life. Since Hydrogen peroxide is a very potent by-product of metabolism, if not decomposed very fast it can cause damage to body cells (Chelikani, Fita & Loewen, 2004). 8.0 Conclusion This experiment has helped to study the rate at which catalase produces oxygen in various concentrations of hydrogen peroxide, in a pureed potato. It has been evident that the rate of reaction is high at low concentrations of hydrogen peroxide, but this rate reduces as the concentration is increased. When the reaction attains saturation, the reaction ceases to take place. The rate of reaction increases because more substrates are getting an opportunity to react with more active regions of the enzyme as concentration of H2O2 is increased. The reliability and validity of the experiment has been quite remarkable because necessary measures were taken to ensure high standards. This includes controlling the room temperature to avoid deviations and by ensuring that the apparatus were maintained at constant conditions across different tests. All the same, considering that the reaction is exothermic and leads to production of heat in the process, this could be expected to interfere with the concentration of hydrogen peroxide, but only to a limited degree that might not interfere with the validity of the results. References Chelikani, P., Fita, I., & Loewen, P.C. (2004). Diversity of structures and properties among catalases. Cell. Mol. Life Sci. 61 (2): 192–208. Read More