Enzymes Laboratory Report
Introduction
The utilization of any complex molecule for energy by an organism is dependent on a process called hydrolysis. Hydrolysis breaks complex molecules into simpler molecules using water. Similarly, the process that is the reverse of this is called dehydration synthesis, which removes water from simpler molecules. However, because hydrolysis occurs very slowly, living organisms use biochemical’s called enzymes to speed up the reaction.
In this lab exercise, we studied the nature of enzyme actions using live yeast cells as our source of sucrose. The enzyme will then break the sucrose into one molecule of glucose and fructose. Because sucrose is a large molecule that cannot enter most cells, yeast will produce sucrase and secrete it into cell membranes. The sucrose will be hydrolyzed into small six-carbon monosaccharide’s which can enter into the cell membranes. The sucrose can be obtained from a 0. 5 percent solution of “dry baker’s yeast in water”.
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In parts A and B, the experiment will study the optimal temperature under which the yeast cells degrade sucrose using varying pH and temperature of the environment surrounding the yeast cells. Part C will study the effects of extreme heat on enzyme activity and part D will focus on the saturation point for enzymes using varying substrate concentrations.
Materials and Procedure See pg 79-82 section: Enzymes “Experiments in Biology from Chemistry to Sex” Fifth Edition By Linda R. Van Thiel Results In test A. ffect of pH, the results we obtained for tube #1 was a solution color of orange and a color activity of 3. For #2 was also orange and color activity of 3. For #3 was orange and a color activity of 3, for #4 was green and a color activity of 1, and finally for #5 was blue and a color activity of 0. From our results, it shows the optimum pH is tube # 1-3. The control in this experiment was test tube 3A, with a pH of 7, as this pH was neutral. In test B. effects of temperature, the optimum temperature is shown on our graph to be two different points (either 24 or 60 degrees).
For our results we received a solution color of blue for tube 1, and a color activity of 0. For tube 2, we received a solution color of orange and a color activity of 3. For tube 3, we received a solution color of green and a color activity of 1, for tube 4; we received a solution color of orange and a color activity of 3. Finally, for test tube 5, we received a solution color of blue, and a color activity of 0. The highest rates of activity were found in test tubes 2 and 4.
The control in this experiment was test tube number 2, which was kept in the temperature environment of 24C [room temperature]. In test C. Effect of Denaturation, the boiled sucrose and sucrase received slightly lowered color activities than the non-boiled tube. Shown on graph 8. 3, the graph begins with no movement in rate of activity followed by a steady increase in the color activity. The results show that test tube 1, which was boiled sucrase and sucrose, had a solution color of green and a color activity of 1.
Test tube 2, which contained boiled sucrase had a solution color of green and a color activity of 1, test tube 3, which contained boiled sucrose, had a solution color of orange and a color activity of 3, finally test tube 4, which was neither boiled, had a solution color of red, and a color activity of 4. From the results, the neither boiled tube had the highest color activity. The control in this experiment was test tube 4, which was completely untouched. In test D. Effect if substrate concentration, the higher concentrations of sucrose received a higher color activity.
The graph is represented by a constant followed by a steady drop as the concentration of sucrose decreases. The results showed that in test tube 1, which contained 100% of sucrose, the solution color was red and the solution gained a color activity of 4. In test tube 2, the concentration of sucrose of 50%, and the solution color was also red, which a color activity of 4. In test tube 3, which contained 25% sucrose, the solution color was orange, and had a color activity of 3, in test tube 4, which contained 10% concentration; the solution color was green and had a color activity of 1.
In the last test tube, which had no concentration of sucrose, the solution color was blue, and had no color activity. The control in this experiment was test tube 5 which contained no sucrose at all. Discussion In the first test, the test of the effect of pH, the results show the effect of pH increases the rate of reaction as having a slightly acidic pH will increase the actual reaction while supporting a more basic pH will decrease the reaction. In our results, it shows that the pH reaches an optimum pH of 7 before decreasing.
The results are not completely accurate, as the first three tubes all had a color activity of 3. The actual results should have had a slightly higher color activity for the optimum pH (which would have been from a pH of 5-6) and a lower color activity for the starting and ending pH. Experimental error may be caused by unwashed test tubes and slightly inaccurate amounts of solution being placed into test tubes. The second test consisted of the effects of Temperature. Temperature (as represented in graph 8. 2) increases rate of reaction in the enzyme until reaching an optimum point, and then decreasing rapidly.
However, in our results, we were accurate until we reached the optimum point, (37 degrees). Instead of this being the highest point for rate of reaction, we obtained a color activity of 1. Because 37 degrees was the optimum temperature, this should have been the highest point and the highest rate of activity. However, we had an experimental error in the form of accidently placing the 3rd tube in the wrong temperature environment. The third test consisted of the effects of Denaturation. In this test, the tube that showed the highest color activity was tube four because it was not exposed to the higher temperatures.
Enzymes that are boiled, or exposed to extreme temperatures could denature the protein component thus destroying the enzyme. However, by boiling the substrate, the enzyme’s rate of reaction increases. However in our data, the first and second test tube should have contained no color activity as such extreme temperature would have already destroyed the enzyme. There could have been experimental error in the length it took to boil the test tube as it may not have reached its required amount. The last test consisted of the Effects of Sucrose Concentration.
By increasing the amount of substrate, the rate of reaction will also increase as it is more likely that substrate molecules are closer to an enzyme molecule. However, this is only true to a certain limit as demonstrated in the chart. Both test tube 1 (which contains 100% of sucrose) and test tube 2 (which contains 50% of sucrose) have the same color activity despite the significant difference in concentration. This is because the concentration of substrates has reached an approximate saturation point, which is seen in this enzymatic reaction to be 50%.
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