How does diffusion work?

Question

How does diffusion work?

Answer 1

diffusion is the constant,random motion producing a net movement of molecules of substances from a region where there is higher concentration to a region where there is lesser concentration

Answer 2

Diffusion is movement of molecules of a liquid or a gas from an area of high concentration to one of lower concentration (down a concentration gradient). Diffusion occurs until the molecules are evenly spread out.

Diffusion into and out of cells occurs across a selectively permeable membrane and is a form of passive transport as it does not involve energy (ATP) expenditure. Molecules will pass across the membrane as long as

1. They are small enough to pass through the pores in the membrane.

2. they are in solution.

3. A concentration gradient exists.

Hope this helps!