What term describes the process of water moving through a selectively permeable membrane?

• A. Filtration
• B. Exocytosis
• C. Osmosis
• D. Facilitated diffusion

Answer: (C)

The process described here refers specifically to osmosis, which is the movement of water across a selectively permeable membrane. This process is driven by the concentration gradient of water itself; water will naturally move from an area of lower solute concentration to an area of higher solute concentration in an attempt to achieve equilibrium.

The selectively permeable membrane allows water molecules to pass through while restricting the movement of solutes, which is a key characteristic of osmosis. This movement is vital for biological systems, as it plays a crucial role in maintaining cell turgor, regulating fluid balance, and facilitating various physiological processes within organisms.

Other terms related to movement across membranes involve different mechanisms. Filtration typically refers to the movement of substances across a membrane driven by pressure rather than concentration gradients. Exocytosis involves the process of vesicles fusing with the plasma membrane to release their contents outside the cell, and facilitated diffusion refers to the passive transport of molecules across a membrane via specific transport proteins, which primarily applies to molecules other than water. Understanding these distinctions helps clarify why osmosis is the specific term for the movement of water through a selectively permeable membrane.