Question

Two students set up experiments looking at diffusion of starch, glucose, and iodine across a selectively permeable membrane. The first student put starch and glucose inside the dialysis tubing and water and iodine outside the dialysis tubing in the beaker. After 30 minutes, she observed that the iodine diffused into the dialysis tubing, where it reacted with the starch and turned a dark blue-black color. The second student thought he set the experiment up the same way, but he did not observe a color change. What is the most likely mistake that he made when setting up the experiment?

Answer 1

Answer: The second student set up solutions that were in equilibrium.

Explanation: Dialysis is based on the principles of osmosis, meaning the net movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration. If the solute concentrations are the same on each side of the membrane, this spontaneous movement will not occur.

Answer 2

Answer:

answer is C

Explanation:

Starch requires ATP energy for transport and therefore cannot cross the dialysis tubing into the iodine solution.