Question

You will perform an experiment using dialysis tubing. Dialysis tubing is an artificial membrane with specific pore sizes. It is used in dialysis, a process which involves the removal of very small molecules from a solution.

1. In what ways is dialysis tubing a semipermeable membrane?
How would you know?

2.

Predict what you believe will be the changes in movement of water through osmosis in the following instances:

A. Dialysis bag containing distilled water submerged in distilled water.

B. Dialysis bag containing 100% sucrose solution submerged in distilled water.

Answer 1

Answer 1)

Dialysis tube is semipermeable in nature. Because it allows the movement of selectively permeable molecules across the membrane. The water molecules can padd thorugh the dialysis tube's membrane.

Take a dialysis tube containing salt solution and put in distilled water. The water moves to the dialysis tube. This suggests that dialysis tube is semipermeable for water. It does not allow the salt ions to pass through it.

Answer 2)

A) The dialysis bag is filled with distilled water and submerged in distilled water. There is not found any movement of water. Because the water potential is same in dialysis bag as well as in externam solution.

B) In this case, the dialysis bag has 100% sucrose solution. It is placed in distilled water. The water potential is more in external solution as compared to the dialysis bag. The movement of water occurs from high water potential region to lower water potential region. That's why there is found movement of water inside the dialysis bag by the process of endo-osmosis. Because sucrose can not pass through membrane but water can easily pass through it.