Question

What is the source of energy for muscle contraction?

Answer 1

ATP (Adenosine Triphosphate) is the source of energy for muscle contraction. The head of each myosin molecule contains an enzyme called myosin ATPase.

In the presence of this enzyme along with $C{a}^{2+}$ then, and $M{g}^{2+}$ ions the ATP molecule breaks down into ADP and inorganic phosphate, thus releasing energy in the head of myosin.

$ATP\to ADP+P_i+\text{Energy}$

Energy fron ATP causes energised myosin to cross bridges and to bind with actin and in this way initiates contraction.