Example of Facilitated Diffusion. In the cell, examples of molecules that must use facilitated diffusion to move in and out of the cell membrane are glucose, sodium ions, and potassium ions. They pass using carrier proteins through the cell membrane without energy along the concentration gradient.
Then, what are some substances that move through the membrane by facilitated diffusion?
Certain small nonpolar substances, such as oxygen, can diffuse directly through the membrane in a process called simple diffusion. Large, polar or charged molecules and ions either cannot squeeze through the small membrane spaces or are repelled by the hydrophobic membrane interior.
What is needed for facilitated diffusion?
The solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. This process is called passive transport or facilitated diffusion, and does not require energy.
What are the substances involved in diffusion?
|Example||Substance(s) involved||Moved from (high concentration region)|
|Gas exchange in lungs||Carbon dioxide||Blood circulating through lungs|
|Gas exchange in a leaf||Carbon dioxide||Air outside the leaf|
|Exchange in the small intestine||Digested food molecules, eg amino acids and glucose||Small intestine|