Part A. Carbohydrate Digestion

Macerated coleoptiles, water, and Benedict's solution

1) Is there a color change in the solution? Is this a positive or negative Benedict's test?

2) Which substance was oxidized?

3) Which substance was reduced?

4) Do ungerminated corn seeds store sugar or starch?

5) What is responsible for the conversion of starch to sugar in a seedling?

6) Of what advantage to the plant is the presence of two forms of carbohydrates?

Part B: Protein Digestion

Pineapple and hard-boiled egg white

1) What happens to the egg white in the two tubes? Hint: you must carefully look at the edges of the cooked egg white.

2) What effect does boiling have on the enzyme bromelin?

3) Would you expect all enzymes to act similarly if they were boiled? Why?

Part C: Starch Digestion in Animals

Soda cracker and Benedict's solution

1) Does a color change occur?

2) Is this a positive or negative test for a reducing sugar?

Saliva and Benedict's solution

1) Does your saliva contain reducing sugar?

2) Does it contain starch?

Saliva, soda cracker, and Benedict's solution

1) Does the partially digested cracker contain reducing sugar?

2) Does it contain starch?

3) What was responsible for the conversion of carbohydrate from one form to another?

4) Where in the body does the final digestion of carbohydrates occur?

5) Would you expect to find the digestion of protein and fats occurring in the mouth? Explain.