Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a on the t tubule and a on the membrane of the sarcoplasmic reticulum.

1) Dihydropyridine receptor

2) Rynodine receptor

Explanation:

Rynodine receptor: It is a category of interacellular channels of calcium with different forms like neurons and muscles found in animal tissues.

Dihydropyridine receptor: they are present in muscle tissues and are able to sense voltage in skeleton muscles thus can increase or control the release of calcium.

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.

12 is it do you think so