Respuesta :

Answer:

The word ‘diffusion’ means free movement across distance, with or without the presence of a barrier. However, there is a phenomenon known as facilitated diffusion which occurs at the cellular level. The cell does not allow free radicals and other harmful substances to enter and harm the cell organs.

Explanation:

Answer:

When certain large molecules are unable to move through the membrane without the help of channel proteins.

Explanation:

Facilitated diffusion occurs when large molecules that are unable to pass through a membrane on their own make use of channel proteins to move from one side of the membrane to the other. Facilitated diffusion can occur when a liquid on one side of a membrane has a higher osmotic pressure than a liquid on the other side of the membrane, but it isn’t a required feature of facilitated diffusion. Similarly, facilitated diffusion can occur when there’s a large membrane potential present, but it isn’t a required feature of facilitated diffusion. Facilitated diffusion doesn’t require the use of energy, so the presence of ATP is irrelevant to facilitated diffusion occurring.