Osmosis causes water to move from areas of low salt concentration to areas of high salt concentration.
The internal NaCl concentration of red blood cells is 0.9 M. The diagram below shows red blood cells submerged in solutions of four different NaCl concentrations—0 M, 0.65 M, 0.9 M, and 2 M.
red blood cell osmosis
Which of the diagrams shows red blood cells in the 0.65 M solution?
A.
1
B.
4
C.
3
D.
2
B. 4
To determine which diagram shows red blood cells in the 0.65 M solution, we need to understand how osmosis works.
Osmosis is the movement of solvent (in this case, water) molecules from an area of low solute concentration to an area of high solute concentration through a semipermeable membrane (such as the cell membrane). In this case, the solute is NaCl (salt) and the solvent is water.
Given that the internal NaCl concentration of red blood cells is 0.9 M, we know that the red blood cells have a higher salt concentration compared to a solution with 0.65 M NaCl. In other words, the red blood cells have a relatively higher solute concentration than the 0.65 M solution.
To determine which diagram shows red blood cells in the 0.65 M solution, we are looking for a diagram where the red blood cells are surrounded by a solution that has a lower solute concentration (in this case, lower NaCl concentration) than the red blood cells themselves.
Looking at the diagrams provided:
1. The red blood cells are surrounded by a solution with 0 M NaCl concentration, which is lower than the red blood cells' concentration of 0.9 M NaCl. Therefore, this diagram does not represent the 0.65 M solution.
2. The red blood cells are surrounded by a solution with 2 M NaCl concentration, which is higher than the red blood cells' concentration of 0.9 M NaCl. Therefore, this diagram does not represent the 0.65 M solution.
3. The red blood cells are surrounded by a solution with 0.9 M NaCl concentration, which is the same as the red blood cells' concentration. Therefore, this diagram does not represent the 0.65 M solution.
4. The red blood cells are surrounded by a solution with 0.65 M NaCl concentration, which is lower than the red blood cells' concentration of 0.9 M NaCl. Therefore, this diagram represents the 0.65 M solution.
Therefore, the correct answer is B. Diagram 4 shows red blood cells in the 0.65 M solution.