00:03
In the mitochondria, there's a membrane.
00:05
And remember, membranes are made up of phospholipids, so they have that, those lipid tails of the phosphate heads.
00:12
And so if you can just imagine these all lined up in a long row to make that membrane.
00:19
And on one side, we're going to have a bunch of these hydrogen ions.
00:23
So it's a hydrogen ion is a positively charged ion, and it can't go through this membrane.
00:31
It sort of bounces off because it is too charged to pass through the membrane.
00:37
So when you have a lot of these hydrogen ions on one side of the membrane, it creates what's called a gradient.
00:45
There's a higher concentration on the top of the picture and a very low concentration of hydrogen ions on the bottom of the picture.
00:53
And the natural tendency in that situation is for things to spread out evenly.
00:58
If you think about like spraying perfume in a room, it's very concentrated on one side of the room, but then over time will spread to the other side of the room...