21/07/2025
π§ What is Osmosis?
Osmosis is the movement of water molecules through a semi-permeable membrane from an area of low solute concentration (more water) to an area of high solute concentration (less water) β aiming to balance concentrations on both sides.
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π Key Facts:
1. Passive Process
Osmosis doesnβt require energy. Itβs a type of passive transport, relying on natural concentration differences.
2. Occurs Through Semi-Permeable Membranes
Only water (and sometimes small molecules) can pass β not salts, sugars, or larger molecules.
3. Important in Cells
Osmosis helps regulate water balance in animal and plant cells. Too much or too little water can make cells swell or shrink.
4. Plant Turgor Pressure
In plants, osmosis gives rise to turgor pressure, keeping stems and leaves firm. Without it, plants wilt.
5. Hypertonic vs Hypotonic vs Isotonic
β’ Hypertonic solution: Water moves out of the cell β cell shrinks
β’ Hypotonic solution: Water moves into the cell β cell swells
β’ Isotonic solution: No net water movement β cell remains the same
6. Reverse Osmosis
This is a man-made process that uses pressure to force water through a membrane, removing impurities β often used in water purification.
7. Medical Relevance
Osmosis explains how IV fluids must be isotonic to avoid damaging red blood cells.
8. Osmotic Pressure
This is the pressure needed to stop osmosis β a concept important in chemistry and biology.
