Question

Students investigated how kidneys function by creating four model cells from dialysis tubing. The students made each cell by sealing one end of the tube with thread and filling it with a 10%-solution (by volume) of blue dye in water. Then, the students made each cell watertight by sealing the other end of the tube with thread.

Each model cell began with a mass of 10 grams. The students placed one model cell into four different beakers. Each beaker contained a different solution concentration of blue dye in water. After 24 hours, they recorded the mass of the model cells. Their data is shown in the table.

Beaker Solution Concentration (% Volume) Mass of Model Cell (g)
1 0 12
2 10 10
3 20 9
4 30 8
Which statement best describes why the mass of the model cell in Beaker 1 is 12 grams after 24 hours?

A.
It began with the greatest concentration of blue dye solution of any model cell in the experiment.

B.
It began with the smallest concentration of blue dye solution and the most water of any model cell in the experiment.

C.
Water moved out of the model cell into the beaker, causing the concentration of the cell solution to become greater than the concentration of the beaker solution.

D.
Water moved into the model cell from the beaker to equalize the concentrations of the model cell solution and the beaker solution, causing the mass of the cell to increase.

Answer 1

D

Beaker 1 contained pure water (0% dye) while the model cell held 10% dye. Water moved by osmosis through the dialysis tubing into the cell to dilute its higher solute concentration, increasing the cell’s mass from 10 g to 12 g.