What term describes the movement of water across a semi-permeable membrane?

The movement of water across a semi-permeable membrane is accurately described by the term osmosis. Osmosis specifically refers to the process where water molecules move from an area of lower solute concentration to an area of higher solute concentration through a semi-permeable membrane. This type of movement is essential for maintaining the proper balance of water and solutes in cells, playing a critical role in various biological functions, such as nutrient absorption and waste removal.

In contrast to osmosis, diffusion refers to the movement of solute particles from an area of higher concentration to an area of lower concentration. Active transport involves the movement of molecules against their concentration gradient, which requires energy. Endocytosis is a process where cells engulf substances to bring them inside, which is not directly related to the movement of water across membranes. Understanding osmosis is fundamental in biology, particularly in cellular processes, as it affects how cells interact with their environment.