Osmosis

• Osmosis refers to the movement of water molecules from an area of higher concentration to an area of lower concentration through a semi-permeable membrane.
• This passive process requires no energy from the cell, unlike active transport.
• A semi-permeable membrane is a barrier that allows certain substances to pass through while blocking others. In the context of osmosis, it allows water molecules to move freely while blocking larger solute particles.
• If a cell is placed in a solution of a higher concentration than its interior (a hypertonic solution), water will leave the cell, causing it to shrink. This process is known as plasmolysis.
• Conversely, when a cell is in a solution of lower concentration than its interior (a hypotonic solution), water will enter the cell, which can cause it to burst or lyse.
• In an isotonic solution, where the concentrations inside and outside the cell are the same, there is no net movement of water, but water molecules will still move into and out of the cells at an equal rate.
• Osmosis plays a crucial role in biology. It helps plant cells maintain turgidity, aids in the transport of nutrients in the body, and regulates the hydration levels of cells.
• Lastly, understand that osmosis and diffusion are both processes that drive movement of molecules from a region of higher concentration to one of lower concentration. However, osmosis specifically pertains to the movement of water molecules, and occurs only across a semi-permeable membrane.