ATI Pathophysiology Practice Exam

What term describes the movement of water from an area of high concentration to low concentration through a semipermeable membrane?

1. Active transport

2. Diffusion

3. Osmosis

4. Facilitated diffusion

The correct answer is: Osmosis

The correct term for the movement of water from an area of high concentration to low concentration through a semipermeable membrane is osmosis. Osmosis specifically refers to the passive movement of water molecules across a semipermeable membrane. This process occurs until there is an equilibrium of water concentration on both sides of the membrane. In osmosis, water moves without the need for energy input, relying instead on the concentration gradient of solutes in the solution. This movement is crucial for maintaining proper hydration and cellular function, as cells often need to regulate their internal water balance based on osmotic pressure. The other terms reflect different processes. Active transport involves the movement of substances against their concentration gradient, using energy (usually in the form of ATP). Diffusion refers to the movement of molecules from an area of high concentration to an area of low concentration but does not specify that it is water or through a semipermeable membrane. Facilitated diffusion allows substances to cross membranes with the help of transport proteins but is still driven by concentration gradients and does not specifically refer to water.