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Current time:0:00Total duration:3:04

Video transcript

in the first video where we introduced the idea of diffusion and concentration gradients we had a container with only one type of particle in it we had these purple particles and in our starting scenario we had a higher concentration of the purple particles on the left-hand side than we had on the right-hand side and so if we looked at its concentration gradient so the concentration gradient went from high concentration on the left to low concentration on the right and we saw what happened you had a higher price since you have more of these particles here and they're all bouncing around in different directions randomly you have a higher probability of things moving from the left to the right then from the right to the left you you will have things move from the right to the left but you're gonna have more things you have a higher probability of things moving from left to right and so if you let some time pass then they become more uniformly spread across a container they have moved down their concentration gradient to make things more uniform now what's interesting about this diagram is I've introduced a second particle these big yellow particles and we see that their concentration gradient is going in the other direction so we have a low concentration in fact we have no on the left hand we have we have no we have none of the yellow particles on the left hand side and we have a high concentration on the right hand side so their concentration gradient goes from right to left and the whole point of this video is to show that each particle moves down its unique concentration gradient assuming that it's not blocked in some way it's going to move down its unique concentration gradient irrespective of what the other particles are going to do for the most part and so we see the yellow particles are going to move from high concentration to low concentration they're going to move they're going to diffuse from right to left and once again there is no magic here though it's not like this molecule say oh I got I got seven other of my friends here it's getting too crowded I see them I'm claustrophobic let me move on to the left hand side that's not what's going on they're just all randomly bouncing around and when you're in the starting position when when you're exactly like this there's no probability because of something of a yellow particle moving from left to right because there aren't any yellow particles here Wow seven well there's a probability that some of these particles and in a certain amount of time some of these yellow particles could move from right to left and so they'll keep doing that until you get to a stable configuration where now you have an equal probability of things moving from left to right and right to left and that's going to be true for each of these particles so what I wanted the real takeaway you'll hear in a biology or chemistry class of things moving down their concentration gradient and you might say in their unique concentration gradient as you see the yellow particles concentration gradient goes in the other direction as the purple particles but there's no magic to this is you just have to imagine a bunch of things just bouncing around in a bunch of different directions and then what would just naturally happen you would naturally have a higher probability of moving from high concentration to low concentration than from low concentration to high concentration
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