00:01
This question asks, with which of the following molecules does calcium bind after it's released from the sarcoplasmic reticulum to regulate muscle contraction? our answer choices are myocin, actin, troponin, and tropomyosin.
00:16
Well, we know that calcium is actually going to be released from the sarcoplasmic reticum into the sarcoplasm.
00:22
Why is it released? well, these calcium ions are actually going to bind to troponin molecules.
00:39
With the goal of releasing the myosin binding sites from their binding to tropomyosin.
00:51
Basically what happens is there's tropomycin, which is going to sit on top of our myosin binding sites, preventing myocin from binding to our actin filament.
01:02
So if we take a look, let's say that this is going to be our actin filament right here, our thin filament, and we'll have troponin, no, we're going to have tropomycin, which is going to sit right on top of it.
01:16
It's going to sit right on top of there...