Which statement below best describes the role of Ca ++ in muscle contraction? A. Ca ++ binds to troponin, thereby changing its shape to expose the binding site. B. Ca ++ causes ADP and inorganic phosphate to detach from the myosin crossbridge. C. Ca ++ attaches to the myosin head, causing it to disengage from its binding site. D. Ca ++ crosses the sarcolemma from the axon terminal which allows the action potential to propagate along the sarcolemma.
Option A. Ca++ binds to protein complex troponin , thereby changing its shape to expose binding site. ATP then binds to myosine, releasing the myosine head from the active site of actine.
