REVIEW SHEET EXERCISE 8 Chemical and Physical Processes of Digestion NAME: Courtney Boyd LAB TIME/DATE: July 23, 2010 Carbohydrate Digestion The following questions refer to Activity 1: Assessing Starch Digestion by Salivary Amylase. 1. At what pH did you see the highest activity of salivary amylase? pH 7.0 . Why? • This is because these were able to break down sugars such as glucose and maltose and convert them into starch. 2. How do you know that the amylase did not have any contaminating maltose? • I know that the amylase did not have any contaminating maltose because there was no starch present. 3. What effect did boiling have on enzyme activity? Why? • It showed that there was starch present and no presence of reducing sugars. This is because it was used as a control to show which comparisons can be made against a standard. 4. Describe the substrate and the subunit product of amylase. • The substrate and the subunit product of amylase are starch and maltose. Starch decreases during the digestion process as sugar increases and starch is then digested into maltose. The following questions refer to Activity 2: Assessing Cellulose Digestion. 5. Does amylase use cellulose as a substrate? Explain. • No, amylase cannot use cellulose as a substrate because it is only able to use or digest starch and starch can be easily broken down into a disaccharide such as maltose. Cellulose is mainly found in plant walls; however, humans pass it through the digestive system as roughage or fiber. 6. Did freezing have an effect on the activity of amylase? Explain.
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