In which direction does the net movement of water occur when a cell is placed in a hypertonic isotonic or hypotonic solution
The correct answer and explanation is:
Correct Answer:
- Hypertonic solution: Water moves out of the cell.
- Isotonic solution: No net movement of water.
- Hypotonic solution: Water moves into the cell.
Explanation:
The direction of water movement across a cell membrane is governed by osmosis, which is the passive movement of water molecules from an area of low solute concentration to an area of high solute concentration. This movement continues until equilibrium is reached or is resisted by cellular structures like the cell wall or membrane.
When a cell is placed in a hypertonic solution, the external environment has a higher solute concentration than the fluid inside the cell. Because water moves from regions of lower solute concentration to higher solute concentration, water will exit the cell. This can cause animal cells to shrink or undergo crenation, and in plant cells, it may lead to plasmolysis, where the cell membrane pulls away from the cell wall.
In an isotonic solution, the solute concentration is equal inside and outside the cell. There is still movement of water across the membrane, but it occurs equally in both directions. This balance means that the cell maintains its normal shape and size. Isotonic environments are ideal for animal cells because there is no swelling or shrinking.
In a hypotonic solution, the surrounding fluid has a lower solute concentration than the inside of the cell. Water moves into the cell, where the solute concentration is higher. This can lead to swelling of the cell. In animal cells, this may cause the cell to burst (lyse), while plant cells become turgid due to the pressure of the water against the cell wall, which prevents bursting.
Understanding these principles is essential in fields like biology and medicine, where fluid balance and cell stability are critical for proper physiological function.