Question

When is facilitated diffusion necessary?

When the molecules are too large.
When the molecules are insoluble.
When the direction of movement is opposite to Natural diffusion.
None of the above

Answer 1

When the molecules are too large.

Step-by-step explanation:

Answer 2

When the molecules are too large.

Step-by-step explanation:

Facilitated diffusion refers to the passive transport of substances down the concentration gradient via specific transport proteins present in the membrane. The large, polar, charged substances and ions cannot pass through the small spaces present between hydrophobic tails of membrane phospholipids. The transport proteins transport these substances in energy independent manner.