Question

What characteristics are 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 semipremeable 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 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 higher concentration to lower concentration without cellular energy.

Movement of substances from a region of high to low concentration takes place until equilibrium is achieved. If the transport takes place with the help of a transporter protein embedded in the plasma membrane, it is called facilitated transport, for e.g. transport of glucose. Thus, diffusion is similar to facilitated diffusion as transport of molecules takes place from a region of high concentration to low concentration without the requirement of energy.