Question

Read the following passage and answer the following questions.
Dialysis tubing is a semipermeable membrane. It allows small molecules, such as water, to pass through easily, while larger molecules, such as sucrose, are restricted. Movement of molecules across the tubing is due to concentration gradients. In an experiment designed to study osmosis, several pieces of dialysis tubing were filled with sucrose solutions of varying concentration and placed in beakers containing distilled water. The rate and direction of water movement was determined by weighing the bags before and after placing them in the distilled water. The data are recorded below.Table 1

Tube number	Tube contents (beaker contents)	Mass(g) 0 minutes	Mass (g) 15 minutes	Mass (g) 30 minutes	Mass (g) 45 minutes	Mass (g) 60 minutes
1	Distilled water (distilled water)	22.3 g	22.4 g	22.2 g	22.3 g	22.3 g
2	10% sucrose (distilled water)	24.8 g	25.3 g	25.7 g	26.4 g	26.9 g
3	40% sucrose (distilled water)	25.1 g	26.3 g	27.5 g	28.9 g	29.6 g
4	Distilled water (40% sucrose)	22.7 g	21.3 g	20.5 g	19.8 g	18.7 g

Cell membranes are also semipermeable, allowing water but not other substances to cross easily. A red blood cell placed in a 0.9% NaCl solution will neither swell nor shrivel. Based on this knowledge, and the information presented in Table 1, what would happen to a red blood cell placed in a 20% NaCl solution?

• A. Water would be drawn out of the cell and the cell would swell
  
• B. Water would be drawn into the cell and the cell would swell
• C. Water would be drawn out of the cell and the cell would shrivel
• D. Water would be drawn into the cell and the cell would shrivel
• E. No change would occur to the cell

Answer 1

Answer: (C)

Water would be drawn out of the cell and the cell would shrivel

The concentration of solute inside the cell (0.9% NaCl) is lower than outside of the cell (20% NaCl). Hence the solvent molecules (water) will move from a region of lower solute concentration to higher. Hence water comes out of the cell and it shrinks.

So, the correct answer is option C.