Question

Which type(s) of molecules will not move into or out of the bag?

A. Both water and iodine
B. Starch only
C. Iodine only
D. Water only

Answer 1

The experiment shows that molecule size is key for movement through the dialysis membrane, as smaller fructose molecules could diffuse through it, whereas larger lactose molecules could not.

Step-by-step explanation:

In the described experiment, the fact that fructose is detected in the distilled water outside of the dialysis-tubing bag, but lactose is not, leads to the conclusion that molecule size affects the movement of molecules through the dialysis membrane. Fructose, being a smaller monosaccharide, was able to diffuse through the membrane, thus moving into the distilled water. In contrast, lactose, a larger disaccharide, could not pass through the selectively permeable membrane of the dialysis tubing. This indicates that the dialysis tubing allows for selective permeability based on molecule size.