Both involve the movement of a substance from regions of higher concentration to lower concentration without cellular energy. Though they share this, there are many differences between simple and facilitated diffusion. Simple diffusion does not need any assistance carrying out molecule carrying, while facilitated diffusion does.
Despite needing assistance, facilitated diffusion is faster than simple diffusion. Another difference between them is that simple diffusion is not solute specific and cannot be inhibited by a molecule inhibitor. On the other hand, facilitated diffusion can be solute, and it can be inhibited by a molecule inhibitor.
Diffusion is important as it removes waste on an organism and process the molecules that are useful for the cells. There are two types of diffusion - simple and facilitated diffusion have similarities and differences. For their differences, a diffusion that does not need energy is simple diffusion while facilitate diffusion needs a source of adenosine triphosphate or ATP.
Simple diffusion only occur on prokaryotes (organisms that do not have mitochondria and nucleus) while the facilitated is for eukaryotes. Faciliitated diffusion can be saturated depending on the number of proteins in the functional membrane but simple diffusion cannot be saturated. Their similarity is substance move from higher concentration to lower concentration.