Question

Does diffusion depend on size of substances and solubility in lipids or facilitated diffusion?

Answer 1

Diffusion does depend on the size of the object and solubility in lipids. Those substances that are fat soluble can easily cross the lipid membrane and those that cannot cross the lipid membrane and those that are fat insoluble require a carrier for diffusion and when a carrier is used for diffusion it is known as facilitated diffusion.