When cells are placed in water, the movement of water across the cell membrane depends on the concentration of solutes inside and outside the cell. Specifically, the effect on red blood cells is well-defined.
Osmosis and Red Blood Cells in Water
According to the reference, when red blood cells are placed in pure water (a solution with a higher water concentration than the cell's interior), a process called osmosis occurs. Osmosis is the movement of water from an area of high water concentration to an area of low water concentration across a semi-permeable membrane (like the cell membrane).
- Water Movement: Water will diffuse from the higher water concentration (outside the cell in the pure water) to the lower water concentration (inside the cell).
- Cell Swelling: As water enters the cell, the cell swells up.
- Cell Bursting (Lysis): Because the cell membrane has its limit on expansion, the red blood cell will eventually burst, a process called lysis.
| Condition | Water Concentration | Effect on Red Blood Cell |
|---|---|---|
| Pure Water | Higher (outside) | Swells and bursts |
| Isotonic Solution | Equal | Normal, no net change |
| Hypertonic Solution | Lower (outside) | Shrivels |
In summary, placing red blood cells in pure water leads to a net influx of water into the cells, causing them to swell and ultimately burst due to osmotic pressure. The water moves to dilute the solutes inside of the red blood cell.
