PHYSIOLOGY
MUSCLE STRUCTURE FUNCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What two chemicals are necessary for muscle contraction to occur?
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Sodium and Potassium
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Calcium and ATP
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Sodium and Phosphate
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Acetylcholine and Potassium
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Explanation:
Detailed explanation-1: -(1) Calcium binds to troponin C, causing the conformational shift in tropomyosin that reveals myosin-binding sites on actin. (2) ATP then binds to myosin. (3) ATP is then hydrolyzed.
Detailed explanation-2: -Muscle contraction is driven by the interaction between two proteins, myosin and actin, and fueled by the hydrolysis of ATP.
Detailed explanation-3: -Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.
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