|
Activity 1: Assessing Starch Digestion by Salivary Amylase (pp. 104–105)
10. Tubes 2, 6, and 7 showed the effect of pH on amylase activity. The results of this experiment indicate that the activity maximum of amylase is at pH 7.0, whereas pH 2.0 and pH 9.0 demonstrated very little activity.
In this experiment, pH 7.0 showed the highest level of amylase activity.
Tube 3 showed that amylase did not contain maltose contamination. Tubes 3, 4, and 5 showed that water had no starch or maltose contamination. Tube 3 directly showed that water did not have maltose or starch contamination. Tube 4 was a starch control (with the same water) that showed no maltose, and tube 5 was a maltose control (also with water) that showed no starch.
If control tubes 3, 4, or 5 were not done, then what is perceived as digestion might really be starch or maltose contamination. Saliva would not be active in the stomach because the stomach pH is too low. Boiling inactivates, or denatures, enzymes.
Activity 2: Assessing Cellulose Digestion (pp. 105–107)
10. Tubes #4, 5, and 6 showed that starch or cellulose was still present. Tubes #1, 2, 3, and 7 showed positive tests for the Benedict’s reagent, indicating the presence of reducing sugar. Freezing had no effect. Freezing does not restrict enzyme activity, unlike boiling. Amylase had no effect on the cellulose in tube #4. Cellulose is digestible by bacteria. Peptidase had no effect on animal starch. Peptidase does not work on carbohydrate substrates so has no effect on digestion of these molecules.
|
Quick Reply
