AQA GCSE Biology Paper 1 Practice Exam 2026 – All-in-One Guide to Exam Excellence!

The physiological process that refers to the movement of water through a partially permeable membrane is osmosis. Osmosis is a specific type of passive transport that involves the diffusion of water molecules from an area of higher water concentration (or lower solute concentration) to an area of lower water concentration (or higher solute concentration), across a partially permeable membrane. This process is crucial for maintaining cell turgor and overall homeostasis in biological systems, allowing cells to regulate their internal environment effectively.

In contrast, filtration involves the movement of solutes and solvents through a membrane due to pressure, rather than concentration gradients, and is not specific to water. Diffusion, while a similar concept, pertains to the movement of solutes or gases rather than specifically water. Active transport requires energy to move substances against their concentration gradient, which is fundamentally different from the passive nature of osmosis. Understanding this distinction reinforces why osmosis is the correct answer regarding water movement across membranes.