00:01
The concentration of calcium ions is much higher outside the cell.
00:05
So what happens? a, calcium spontaneously diffuses across a membrane into the cell.
00:12
B, spontaneously exits by facilitated diffusion, diffuses out of the cell, unaided, or spontaneously diffuses into the cell by facilitated diffusion.
00:25
So there are two parts here.
00:26
First of all, which direction is the calcium going to be going? second is it's simple diffusion or facilitated.
00:32
So we'll start the direction.
00:34
So we're looking at diffusion, which is passive, and is always down the gradient.
00:41
So because the concentration is so much higher outside the cell, it's going to be entering the cell.
00:50
So it's going down the gradient into the cell.
00:53
So let's rule out the ones that talk about exit...