What ion is necessary for cross-bridging?
A)Iron
B)Sodium
C)Potassium
D)Calcium

Question

Quizplus · Accepted Answer

Calcium ions are necessary for cross-bridging in muscle contraction. When a muscle is stimulated by a nerve impulse, calcium ions are released from the sarcoplasmic reticulum and bind to the protein molecule troponin, causing a conformational change that exposes the myosin-binding sites on actin. This allows the myosin heads to form cross-bridges with actin and initiate the sliding filament mechanism of muscle contraction. Without calcium ions, the muscle would not be able to contract effectively.

What Ion Is Necessary for Cross-Bridging