Question

Elizabeth is conducting an investigation to study how molecules are transported into and out of a cell. Elizabeth builds a model of a cell using a U-shaped tube. A barrier, which is permeable to water, but not sugar, is placed on the bottom of the tube to model the cell membrane. Elizabeth adds two different solutions to each side of the tube. The solute in each solution is sugar and the solvent is water. The initial levels of solution in Side A and Side B are equal. The concentration of sugar in Side A is lower than the concentration of sugar in Side B.
What is Elizabeth likely to observe?

A. Water molecules will move from Side A to Side B. The solution level on Side A will fall and the solution level on Side B will rise.
B. Water molecules will move from Side B to Side A. The solution level on Side A will rise and the solution level on Side B will fall.
C. Sugar molecules will move from Side A to Side B. The solution level on Side A will fall and the solution level on Side B will rise.
D. Sugar molecules will move from Side B to Side A. The solution level on Side A will rise and the solution level on Side B will fall.

Answer 1

The correct answer is A

Answer 2

The correct answer is: A. Water molecules will move from Side A to Side B. The solution level on Side A will fall and the solution level on Side B will rise.

Because the barrier is permeable only for water, water will move via osmosis-down the gradient (into a area of higher solute concentration). Water tends to equalize the solute concentrations of the side A with the solute concentrations of the side B.