Final answer:
The statement is true: myosin heads at one end of a thick filament move a thin filament in one direction while those at the opposite end move another thin filament in the opposition direction, shortening the sarcomere and facilitating muscle contraction.
Step-by-step explanation:
True - the Myosin II heads at one end of a thick filament in a sarcomere move a thin (actin) filament in one direction, while the myosin heads at the opposite end move another thin filament in the opposite direction. During muscle contraction, thick and thin filaments slide past each other without changing length, a process triggered by electrochemical signals from nerve cells. Myosin heads undergo a sequence of binding to actin, pulling, releasing, and re-cocking known as the cross-bridge cycle, driven by the hydrolysis of ATP.
Each myosin head executes what is known as the power stroke, where they pull the actin filament toward the center (M line) of the sarcomere, which results in the shortening of the sarcomere and therefore, muscle contraction. The myosin heads on one side of the filament pull in one direction, while on the other side, they pull in the opposite direction, which effectively draws the Z-lines closer together, increasing the overlap between thick and thin filaments, decreasing the length of the I band and H zone, but keeping the A band's length unchanged.