NCC Certified Electronic Fetal Monitoring (C-EFM) Practice Exam

What is transfer down the concentration gradient from higher to lower called?

1. Osmosis

2. Diffusion

3. Filtration

4. Absorption

The correct answer is: Diffusion

The process of transferring substances down the concentration gradient from areas of higher concentration to areas of lower concentration is known as diffusion. This fundamental concept is essential in understanding how molecules move in biological systems. In diffusion, molecules tend to spread out evenly in a given space, resulting in a net movement that continues until equilibrium is reached, where there is a uniform distribution of particles. This movement occurs naturally, driven by the kinetic energy of the molecules, and does not require energy input from the cell. While osmosis, which involves the movement of water across a selectively permeable membrane, is also a type of diffusion, it specifically pertains to water rather than all substances. Filtration involves the movement of fluids through a membrane due to pressure differences, which is a distinct mechanism, and absorption typically refers to the uptake of substances by cells or tissues. Thus, diffusion is the most accurate term for the described process of substance transfer down a concentration gradient.