Exercise 2 - Questions
Question 1
1. Define diffusion.
2. IKI indicator tests for the presence of which substance? Benedict's reagent tests for the presence of which substance?
3. In the first part of this exercise, a glucose/starch solution was placed in dialysis tubing. Then, the tubing was placed in a cup containing IKI indicator. Did starch stay within the tubing or move out of the tubing? Did IKI indicator stay in the solution in the cup or move into the tubing?
Support your answer with the observations you recorded in Data Table 3.
4. In the second part of this exercise, the IKI solution in the cup and the contents of the dialysis tubing were heated with Benedict's reagent. Did sugar stay move out of the tubing? Support your answer with the observations you recorded in Data Table 4.
5. What was the purpose of testing distilled water with Benedict's reagent?
6. How is a cell membrane similar to the dialysis tubing used in this experiment?
7. Is the movement of substances in this exercise active or passive?
8. From your data, might it be inferred that a) starch and glucose molecules are the same size, b) starch molecules are larger than glucose molecules, or c) starch molecules are smaller than glucose molecules. Use your data to explain your answer.
9. Could the speed at which molecules diffused over the dialysis tubing been slowed down or sped up? If so, explain how.