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”. 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”
By Linda R. Van Thiel
In test A. effect 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....