Animal Cells Rely on Isotonic Environments For Stability
- Animal cells are highly sensitive to their environment because they lack the structural support of a cell wall.
- Water movement across the cell membrane can cause cells to swell, shrink, or remain stable depending on the surrounding solution.
Hypotonic Solutions Cause Cells To Swell and Burst
- In a hypotonic solution, the surrounding environment has a lower concentration of solutes than inside the cell.
- Water moves into the cell by osmosis.
- What happens: The cell swells as water enters, pressure increases, and without a cell wall, the cell membrane may rupture (a process called lysis).
When red blood cells are placed in pure water, they swell and burst, leaving behind empty membranes called "red cell ghosts"
Hypertonic Solutions Cause Cells To Shrink and Crenate
- In a hypertonic solution, the surrounding environment has a higher concentration of solutes than inside the cell.
- Water moves out of the cell by osmosis.
- What happens: The cell loses water and shrinks. The cell membrane pulls away from the cytoplasm, creating a wrinkled appearance called crenation.
Remember: Hypertonic solutions cause cells to shrink, while hypotonic solutions cause them to swell.
ExampleRed blood cells placed in a concentrated salt solution will shrink and develop a spiky appearance due to crenation.
Isotonic Solutions Is Where Cells Are Balanced and Stable
- In an isotonic solution, the concentration of solutes is equal inside and outside the cell.
- Water moves in and out at the same rate, maintaining equilibrium.
