Experiment Results Predict Question: Predict Question: Do you think test tube 3 will show a positive Benedict's test? Your answer : a. yes Stop & Think Questions: You included tube 2 to Your answer : d. make sure there is no contaminating glucose in the amylase. Correct answer: b. see what a positive Benedict's test should look like. Which tube is included to detect contaminating amylase in the buffer or in cellulose? Your answer : b. tube 2 Correct answer: d. tube 4 What is the usual substrate for the pancreatic enzyme peptidase? Your answer : a. starch Correct answer: d. peptides Experiment Data: Tube No. 1 2 3 4 5 6 Reagent 1 Amylase Amylase Amylase Cellulose Peptidase Bacteria Reagent 2 Starch Glucose Cellulose Water Starch Cellulose Reagent 3 pH 7.0 pH 7.0 pH 7.0 pH 7.0 pH 7.0 pH 7.0 Time 60 60 60 60 60 60 Temp. 37 37 37 37 37 37 IKI + + + Benedict's ++ ++ ++
Post-lab Quiz Results You scored 25% by answering 1 out of 4 questions correctly. 1. The substrate(s) for amylase is/are Your answer: b. cellulose. Correct answer: a. starch. 2. The results of tube 5 demonstrated that You correctly answered: b. peptidase does not digest starch. 3. Why was the cellulose in tube 6 hydrolyzed to glucose? Your answer: b. The bacterial suspension contained reducing sugars. Correct answer: d. The bacterial suspension contained the enzyme cellulase, which digested the cellulose. 4. Can you detect the presence of contaminating amylase from your experiments? Your answer: d. There was no contaminating amylase because tube 4 was positive. Correct answer: c. It is not possible to determine whether contaminating amylase is present because amylase doesn't digest cellulose.
Review Sheet Results 1. Describe why the results in tube 1 and tube 2 are the same. You did not answer this question. 2. Describe the result in tube 3. How well did the results compare with your prediction? Your answer: I was correct. 3. Describe the usual substrate for peptidase. You did not answer this question. 4. Explain how bacteria can aid in digestion. You did not answer this question.