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 4: Assessing Fat Digestion by Pancreatic Lipase and the Action of Bile
(pp. 109–111)
7. Tube 1 investigated the action of bile on enzyme activity, and tube 2 examined lipase
activity without bile. Bile enhances fat digestion by lipase.
Yes, you can determine if activity occurred in tube 6 because the pH would drop below
pH 9.0. A small amount of fat digestion occurred because pH decreased from 9.0 to 8.97.
The optimim pH for lipase activity was pH 7.0.
Using a pH method to assay for activity at pH 2.0 does not work because the buffer is
already quite acidic. There could have been activity at pH 2.0 that was not detectable by
this method.
In theory, lipase would be active in the mouth because its pH optimum is relatively neutral.
However, it would not be active in the stomach because of the acidic pH condition.
The substrate is vegetable oil (fat). The subunit formed is fatty acid (and monoglycerides).
hope this helps, if so mark as solved.