Final answer:
An investigation into the effect of pH on amylase activity involves setting pH as the independent variable and measuring the rate of reaction as the dependent variable, while controlling for temperature, amylase concentration, and substrate concentration. The experiment predicts an optimal reaction rate at a pH near 7.0 for human amylase, and includes a method for measuring the rate of starch breakdown into sugar at various pH levels.
Step-by-step explanation:
To investigate the effect of pH on the rate of reaction of amylase, we would first need to identify the different variables involved in the experiment. In this case, the independent variable would be the pH level of the environment in which the reaction is taking place. The dependent variable would be the rate of the amylase-catalyzed reaction, which can be measured by the amount of product formed over time. Controlled variables would include temperature, amylase concentration, and substrate concentration, as these can also affect enzyme activity and must be kept constant to ensure that any changes in the reaction rate are due to changes in pH only.
A prediction could be that the rate of reaction will be highest at the optimum pH for amylase (typically around 7.0 for human amylase) and will decrease as the pH moves away from this optimum. The method would involve preparing a series of buffer solutions with different pH values and then adding a fixed amount of amylase and starch substrate to each one. The reaction would be allowed to proceed for a set time, and the amount of sugar (product) produced would be measured. This could be done by using a colorimetric assay specific for sugars such as the iodine-starch test.
The results that would be collected include the rate of starch breakdown at each pH level, which could be plotted on a graph to show the pH profile of amylase. These results will give insights into the effect of pH on amylase activity and help us understand how pH influences enzyme activity.