PHYSIOLOGY
EXCITATION CONTRACTION COUPLING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What happens when the myosin head splits ATP into ADP and a phosphate group?
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retruns myosin to down (starting) position
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active site on actinbecomes exposed
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cross bridge between actin and myosin forms
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myosin pulls actin towards the midline
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Explanation:
Detailed explanation-1: -The movement of the myosin head back to its original position is called the recovery stroke. Resting muscles store energy from ATP in the myosin heads while they wait for another contraction. Figure 1.
Detailed explanation-2: -The power stroke releases the molecule of ADP from each myosin head. This allows ATP to bind to myosin instead, leading to the breaking of the crossbridge between the actin and myosin filaments and causing the myosin heads to detach.
Detailed explanation-3: -Step 5: The release of inorganic phosphate reinforces the binding interaction between myosin and actin and subsequently triggers the ‘power stroke’. The power stroke is the key force-generating step used by myosin motor proteins.
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