What is osmosis?

Osmosis specifically refers to the movement of water molecules across a selectively permeable membrane. This process occurs from an area of lower solute concentration (where there is a higher concentration of water relative to solutes) to an area of higher solute concentration (where there is a lower concentration of water relative to solutes). Osmosis is a vital biological process because it helps maintain the balance of fluids in cells and tissues, and it's essential for many physiological functions, such as nutrient absorption and waste removal.

In biological systems, osmosis allows cells to regulate their internal environment and maintain homeostasis by controlling water movement. For instance, when plant cells are placed in fresh water, they take up water through osmosis, which helps create turgor pressure that supports the plant structure. In situations where solute concentrations vary, osmosis plays a critical role in how cells adapt to their surroundings, thus sustaining life.

Understanding osmosis is essential since it is distinct from other processes like diffusion of solutes or active transport, which involve the movement of different substances across membranes and often require energy expenditure. In contrast, osmosis is a passive process, driven by the concentration gradient of water, not by the addition of energy.