What does osmosis refer to?

Osmosis specifically refers to the diffusion of water across a selectively permeable membrane. This process occurs when there is a difference in solute concentration on either side of the membrane, leading the water to move from an area of low solute concentration to an area of high solute concentration. The goal of osmosis is to equalize the solute concentrations on both sides of the membrane.

Understanding the nature of osmosis is important, as it plays a critical role in many biological processes, such as maintaining cell turgor pressure in plants and regulating the distribution of fluids in the body. Osmosis is a passive process, meaning it does not require energy, unlike active transport methods which involve the movement of ions or molecules against their concentration gradient using energy. Thus, recognizing the correct definition of osmosis as the diffusion of water is fundamental to grasping more complex biological concepts involving cellular processes and homeostasis.