Explain the role of calcium ions (Ca2+) in the sliding filament theory of muscle contraction? Explain the importance of the proper function of ATP in this process. Theorize what may happen if there were a breakdown of ATP production.

Calcium ions bind to tropomyosin protein which causes a chnage in shape, pulling tropomyosin out of the actin-myosin binding site on the actin filament. It also activated enzyme ATP hydrolase which breaks down ATP to ADP and and inorganic phophate to release energy needed for muscle contraction.

In this process, hydrolysis of ATP (attched to myosin head) causes bending of the myosin head which pulls the actin filament along in a rowing motion.