PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Myosin globular head ‘uncoils’ releasing stored energy.
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Cross Bridges are formed between actin and myosin
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Tropomyosin changes shape (conformation) to expose myosin binding sites.
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Calcium Binds with Troponin
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Detailed explanation-1: -(2) Calcium binds to troponin C, which induces a conformational change in the troponin complex. This causes tropomyosin to move deeper into the actin groove, revealing the myosin-binding sites.
Detailed explanation-2: -Skeletal Muscle Contraction. (a) The active site on actin is exposed as calcium binds to troponin. (b) The myosin head is attracted to actin, and myosin binds actin at its actin-binding site, forming the cross-bridge. (c) During the power stroke, the phosphate generated in the previous contraction cycle is released.
Detailed explanation-3: -Depolarisation and calcium ion release. Actin and myosin cross-bridge formation. Sliding mechanism of actin and myosin filaments. Sarcomere shortening (muscle contraction)