What is the process called when water moves from low solute concentration to high solute concentration across a membrane?

The process of water moving from an area of low solute concentration to an area of high solute concentration across a selectively permeable membrane is called osmosis. This occurs specifically when water molecules pass through the membrane to balance the solute concentrations on both sides. Osmosis is a vital biological process, crucial for maintaining homeostasis in cells, as it influences cell volume and concentration of solutes within the cell.

In contrast to osmosis, diffusion involves the movement of solutes from a region of higher concentration to one of lower concentration; facilitated transport also involves movement down a concentration gradient but typically requires specific transport proteins; and active transport refers to the movement of substances against their concentration gradient, which requires energy input from the cell. Understanding osmosis is key in contexts such as cell biology, where the movement of water is crucial for cell function and health.