Diffusion, in general, is the net movement of particles from areas of high concentration to areas of low concentration. Learn about simple diffusion, channel diffusion and facilitated diffusion with help from a science teacher and field biologist in this free video on chemistry.
Hi, I'm Brian with Ericksontutoring.blogspot.com. Today we're going to talk about different types of diffusion. Diffusion, in general is the net movement of particles from areas of high concentration to areas of low concentration. It's the result of the random constant motion that molecules are always in, but the, the end product is that they move from high to low. There's three main types of diffusion that we want to talk about. Your first type of diffusion is simple diffusion, and basically all that involves is you have your molecules, you have a membrane here, and all these molecules are constantly in motion, moving back, moving all around, but the net result, just because of random motion, is eventually you'll have this high concentration even out and you'll reach a state of equilibrium. The second type is channel diffusion so you end up using channel proteins, which essentially are just little tunnels inside of a cell membrane. So this one is channel diffusion. And here's a really awful diagram of a cell membrane. You have maybe a whole lot of molecules outside and not many inside. Again, as a result of random motion, no energies involved, eventually, more particles that can't get through the membrane on their own, will go through that channel and eventually balance out the, the concentrations. And last, there's a type of diffusion called facilitated diffusion. So, you use a different type of protein in this one. And basically it's a three step process. You have your membrane again, you have high concentration and low concentration, and now we have this protein here that's going to help us. Proteins don't always look like hearts, that's just the way that I draw. So, one of your molecules gets stuck inside of your protein. It sort of clasps onto it, and closes up, and then it flips, and spits it out the other side. So it's a way for larger molecules still that can't pass through the channel and can't go through the membrane on their own, to make it into the other side of a membrane. And that's a little bit about different types of diffusion.