(10 points) In [a] muscle, which lacks obvious [b], Ca2+ ent…
(10 points) In muscle, which lacks obvious , Ca2+ enters the cell through Ca2+ channels and binds to on the SR to increase intracellular Ca2+. These ions then bind to , an evolutionary ancestor of troponin C, which activates . This enzyme then phosphorylates one of the two attached to myosin. This phosphorylation changes the position of the so that it can reach the thin filament which is made of polymerized . Contraction in this muscle type ends when an enzyme called a removes the phosphate group that had been added to the answer in Blank #7.