1. The Cell Membrane:
* The cell membrane is selectively permeable, meaning it allows some substances to pass through while blocking others.
* It's composed of a phospholipid bilayer with embedded proteins.
2. Concentration Gradients:
* Water moves from areas of high water concentration to areas of low water concentration. This is driven by the difference in the concentration of water molecules across the cell membrane.
* High water concentration = low solute concentration (like pure water)
* Low water concentration = high solute concentration (like salty water)
3. Osmosis:
* Water molecules pass through the cell membrane through special protein channels called aquaporins. These channels facilitate the movement of water.
* The direction of water movement depends on the concentration of solutes inside and outside the cell.
* If the concentration of solutes is higher outside the cell, water will move out of the cell. This is called hypertonic solution.
* If the concentration of solutes is higher inside the cell, water will move into the cell. This is called hypotonic solution.
* If the concentration of solutes is equal inside and outside the cell, water moves in and out equally. This is called isotonic solution.
In summary:
* Osmosis is the passive movement of water across a selectively permeable membrane.
* Water moves from areas of high water concentration (low solute concentration) to areas of low water concentration (high solute concentration).
* This movement is facilitated by aquaporins, protein channels embedded in the cell membrane.
* The direction of water movement depends on the relative solute concentration inside and outside the cell.
This process is crucial for maintaining the cell's internal environment, volume, and overall function.
