What term describes the movement of molecules from high concentration to low concentration?

What term describes the movement of molecules from high concentration to low concentration?

• A. Cytosol
• B. Organ
• C. Diffusion
• D. Symbiosis

Answer: (C)

Movement from high concentration to low concentration is diffusion, a passive transport process driven by the random motion of molecules. Because particles are constantly jostling, they spread out from where they are more concentrated to where they are less concentrated until the concentrations are equal. No cellular energy is required for diffusion; it relies on the existing kinetic energy of the molecules and the concentration gradient. How fast diffusion happens depends on factors like how large the concentration difference is, the temperature (which affects molecular motion), how much surface area is available for movement, and how far the molecules have to travel. The nature of the molecule also matters: small, nonpolar molecules diffuse readily through membranes, while larger or polar molecules may need facilitated diffusion via specific channels or carriers. In cells, diffusion explains the movement of gases such as oxygen and carbon dioxide. The other terms refer to parts of the cell or to types of biological relationships, not to a transport process.

Movement from high concentration to low concentration is diffusion, a passive transport process driven by the random motion of molecules. Because particles are constantly jostling, they spread out from where they are more concentrated to where they are less concentrated until the concentrations are equal. No cellular energy is required for diffusion; it relies on the existing kinetic energy of the molecules and the concentration gradient. How fast diffusion happens depends on factors like how large the concentration difference is, the temperature (which affects molecular motion), how much surface area is available for movement, and how far the molecules have to travel. The nature of the molecule also matters: small, nonpolar molecules diffuse readily through membranes, while larger or polar molecules may need facilitated diffusion via specific channels or carriers. In cells, diffusion explains the movement of gases such as oxygen and carbon dioxide. The other terms refer to parts of the cell or to types of biological relationships, not to a transport process.