What process is described by the movement of fluid through a semi-permeable membrane from low solute to high solute concentration?

The movement of fluid through a semi-permeable membrane from low solute concentration to high solute concentration is known as osmosis. This process is specifically characterized by the flow of solvent, typically water, through the membrane, which allows solvents to pass while blocking many types of solute molecules. Osmosis is driven by the concentration gradient; water molecules move to equalize solute concentrations on both sides of the membrane.

This is crucial in biological systems, where cells rely on osmosis to maintain their internal environments and achieve homeostasis. For example, if a cell is placed in a solution with a higher concentration of solutes (hypertonic), water will move out of the cell, causing it to shrink. Conversely, in a lower concentration (hypotonic) solution, water will flow into the cell, leading to swelling. This selective movement is vital for cellular functions, nutrient absorption, and waste removal.