According to the sliding filament theory, when this molecule breaks down, it releases energy that allows Myosin to contract the muscle by pulling the Actin filaments inward, resulting in muscle shortening.
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✓ Correct answer: A. ATPMuscles contract as the myosin heads pull on the actin filaments, shortening the sarcomere. The myosin heads hold both a phosphate and ADP molecule. Initially, the release of the phosphate allows for cross-bridge formation between the myosin heads and the actin binding site.<br/><br/>Subsequently, the release of the ADP molecule enables the myosin heads to pull, initiating a power stroke that shortens the sarcomere. ATP is required to release the cross-bridge and reset the myosin head into a cocked position.
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Theory