Question

What characteristic is shared by simple diffusion and facilitated diffusion?

• A. Both require cellular energy for the transport of substances.
• B. Both involve the movement of water across a semipermeable membrane.
• C. Both require a special carrier molecule to move substances across the membrane.
• D. Both involve the movement of a substance from regions of a higher concentration to lower concentration without cellular energy

Answer 1

The correct option is D

Both involve the movement of a substance from regions of a higher concentration to lower concentration without cellular energy

Diffusion is the movement of molecules from a higher to a lower concentration. Facilitated diffusion is a type of diffusion in which substances move through the cell membrane along a concentration gradient. These substances are insoluble in lipids, hence need the help of a proteinaceous carrier molecule.