Biology Question Ca++ in muscle cells

[21385]

The Kaplan book says that the movement of Ca++ into a muscle cell is ATP-dependent because it says that this movement is against gradient.

However, I thought that there is more Ca++ outside the cell than inside the cell. And for muscle cells, most of the Ca++ ions are stored in the SR and thus would not count towards the intracellular concentration.

Can someone explain this to me?

Thanks a lot!

---

Members don't see this ad.

 

[Charles_Carmichael]

They might mean the ATP-dependent Ca++ pumps that pump calcium out of the cell or into the SR. It's possible it's a typo. I don't have their book in front of me, so I can't say for sure.