PEX 08 01

Name: Lillie Cyr
Exercise 8: Chemical and Physical Processes of Digestion: Activity 1: Assessing Starch Digestion by Salivary Amylase Lab
Report
Pre-lab Quiz Results
You scored 16% by answering 1 out of 6 questions correctly.
1. The substrate for amylase is
Your answer : a. maltose.
Correct answer: e. starch and carbohydrate.
2. Which of the following is true of enzymes?
Your answer : b. They are used up in the reaction.
Correct answer: c. Their activity can be affected by temperature and pH.
3. The reagent IKI tests for the presence of
Your answer : c. glucose.
Correct answer: a. starch.
4. Which of the following is not true of controls?
Your answer : b. With a positive control, a positive result is expected.
Correct answer: 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?
Your answer : b. maltose
Correct answer: 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

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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

+
+

+
+

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Post-lab Quiz Results
You scored 50% by answering 2 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?
Your answer: d. tubes 1, 4, and 5
Correct answer: c. tubes 4, 5, and 6
4. Explain where and why salivary amylase would be most active.
Your answer: a. Salivary amylase would be active in the mouth and the stomach because pH 2 and pH 7 are where its peak activity occurs.
Correct answer: d. Salivary amylase would be most active in the mouth because pH 7 is where its peak activity is.

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Review Sheet Results
You have not completed the Review Sheet.

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