Chemical and Physical Processes of Digestion

Exercise 8: Chemical and Physical Processes of Digestion: Activity 1: Assessing Starch Digestion by Salivary Amylase Lab Report Pre-lab Quiz Results YouThe scored 100% for by answering 1. substrate amylase is 6 out of 6 questions correctly. You correctly answered: e. starch and carbohydrate. 2. Which of the following is true of enzymes? You correctly answered: c. Their activity can be affected by temperature and pH. 3. The reagent IKI tests for the presence of You correctly answered: a. starch. 4. Which of the following is not true of controls? You correctly answered: d. A negative result with a positive control is required to validate the test 5. Which of the following is an end product of starch digestion? You correctly answered: e. maltose and glucose 6. Hydrolases are enzymes that break down large molecules into smaller subunits through the addition of _____________. You correctly answered: b. water 11/28/19 page 1 Experiment Results Predict Question: Predict Question: What effect do you think boiling and freezing will have on the activity of the amylase enzyme? Your answer : c. Boiling will decrease amylase activity and freezing will have no effect. Stop & Think Questions: Tube 2 appears to have the same amount of starch digested as tube 3 because You correctly answered: a. freezing had no effect on the enzyme. Experiment Data: Tube No. 1 2 3 4 Reagent 1 Amylase Amylase Amylase Amylase 5 Deionized Water Deionized Water Amylase Amylase 6 7 8 Reagent 2 Starch Starch Starch Deionized Water Starch Reagent 3 pH 7.0 Buffer pH 7.0 Buffer pH 7.0 Buffer pH 7.0 Buffer Treatment Boiled Frozen None None Time 60 60 60 60 Temp. 37 37 37 37 IKI + - Benedict's ++ ++ - pH 7.0 Buffer None 60 37 + - Maltose pH 7.0 Buffer None 60 37 - ++ Starch Starch pH 2.0 Buffer pH 9.0 Buffer None None 60 60 37 37 + + + + 11/28/19 page 2 Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. Tubes 3, 7, and 8 reveal that You correctly answered: d. amylase activity was highest at pH 7. 2. This activity includes a number of negative controls. Which tube indicates that the amylase solution was not contaminated with maltose? You correctly answered: b. tube 4 3. Which tubes indicate that the deionized water did not contain contaminating starch or maltose? You correctly answered: c. tubes 4, 5, and 6 4. Explain where and why salivary amylase would be most active. You correctly answered: d. Salivary amylase would be most active in the mouth because pH 7 is where its peak activity is. 11/28/19 page 3 Review Sheet Results 1. List the substrate and the subunit product of amylase. Your answer: The substrate of amylase is animal starch and the subunit product of amylase are maltose and glucose. 2. What effect did boiling have on enzyme activity? Why? How well did the results this compare with your prediction? Your answer: Boiling altered the enzyme and deactivated the amylase activity as I predicted. 3. At what pH was the amylase activity the most active? Describe the significance of this result. Your answer: The amylase activity was most active at pH 7.0. This is significant because this is the same pH as the mouth. 4. Briefly describe the need for controls and give an example used in this activity. Your answer: Controls are vital as they are used to verify results of the experiment. For example take test tube #5 where the enzyme that tests for contaminating glucose in the starch is absent. 5. Describe the significance of using a 37°C incubation temperature to test salivary amylase activity. Your answer: The significance of using 37 degrees C on account of this temperature is the same as human body temperature therefore it is ideal for the salivary amylase activity. 11/28/19 page 4