Question

A scientist extracts and measures the calcium content of one of your muscle fibers while you are asleep, when all of your muscles are relaxed. Where is the scientist likely to find calcium?

In the T-tubules

In the sarcoplasmic reticulum

Bound to tropomyosin

Bound to troponin

Answer 1

@e.mccormick

Answer 2

@myininaya

Answer 3

@thomaster

Answer 4

@blues

Answer 5

That's a hard one...
I searched a bit and I think that the sarcoplasmic reticulum would be the most likely place to find calcium in relaxed muscles. This because the sarcoplasmic reticulum releases calcium ions during muscle contraction and absorb them during relaxation.

But I'm not 100% sure.
Perhaps @blues can confirm this.

Answer 6

Okay thanks. Ill continue to research and see how it works out.

Answer 7

When the sarcoplasmic releases Ca2+ during contraction causes an increase in the Ca2+ concentration in the cytosol. The ions then bind to troponin.

Answer 8

OKay that makes sense

Answer 9

but the fact that the sarcoplasmic reticulum stores Ca ions during relaxation would make it more likely that you would find calcium in those cells during sleep.

Answer 10

Right

Answer 11

I agree with thomaster.