Florida State Paramedic Practice Exam

What is the movement of gas from a higher concentration to lower concentration called?

1. Diffusion

2. Osmosis

3. Filtration

4. Active transport

The correct answer is: Diffusion

The movement of gas from an area of higher concentration to an area of lower concentration is termed diffusion. This process occurs naturally as molecules move to attain equilibrium, where they are evenly distributed throughout a given space. In the context of gases, such as oxygen or carbon dioxide, diffusion is critical in biological systems, including the respiratory process, allowing for gas exchange in the lungs and at the cellular level. Osmosis refers specifically to the movement of water across a semi-permeable membrane, driven by a concentration gradient, and is not applicable to gas movement. Filtration involves the passage of fluids through a filter or barrier, typically driven by pressure, rather than concentration gradients. Active transport, on the other hand, involves the movement of substances against their concentration gradient, requiring energy, which contrasts with the passive nature of diffusion. Therefore, diffusion is the appropriate term for the described process.