During muscle contraction, the power stroke is the pivoting motion of the myosin head that pulls the actin filament inward to shorten the sarcomere. Given this, which of the following events most immediately precedes this power stroke motion?A.The binding of ATP to the myosin headsB.The hydrolysis of myosin-bound ATPC.The release of Pi from the myosin headD.The binding of Ca2+ to tropomyosin
Question
During muscle contraction, the power stroke is the pivoting motion of the myosin head that pulls the actin filament inward to shorten the sarcomere. Given this, which of the following events most immediately precedes this power stroke motion?A.The binding of ATP to the myosin headsB.The hydrolysis of myosin-bound ATPC.The release of Pi from the myosin headD.The binding of Ca2+ to tropomyosin
Solution
The event that most immediately precedes the power stroke motion during muscle contraction is C. The release of Pi from the myosin head.
Here's a step-by-step breakdown of the process:
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The process begins with the binding of ATP to the myosin heads. This causes the myosin heads to detach from the actin filament.
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The ATP bound to the myosin head is then hydrolyzed into ADP and inorganic phosphate (Pi). This hydrolysis provides the energy for the myosin head to return to its original position.
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The myosin head, now energized, binds to the actin filament forming a cross-bridge.
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The release of Pi from the myosin head triggers the power stroke. During the power stroke, the myosin head pivots and bends, pulling the actin filament inward and shortening the sarcomere.
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After the power stroke, ADP is released from the myosin head. This makes room for a new ATP molecule to bind to the myosin head, starting the process over again.
So, the event that most immediately precedes the power stroke is the release of Pi from the myosin head.
Similar Questions
he following is a list of the events that occur during a muscle contraction.1. Myosin cross-bridges bind to the actin.2. The free myosin head splits ATP.3. Calcium ion is released from the sarcoplasmic reticulum.4. The myosin head pivots toward the center of the sarcomere.5. Calcium ion binds to troponin.6. The myosin head binds an ATP molecule and detaches from the actin.The correct sequence of these events isQuestion 10Select one:a.3, 5, 1, 2, 4, 6.b.1, 3, 5, 4, 6, 2.c.1, 4, 6, 2, 3, 5.d.3, 5, 1, 4, 6, 2.e.5, 1, 4, 6, 2, 3.
The "cocking" of the myosin heads, hydrolysis of ATP, and the power stroke occur during the Blank______ phase of skeletal muscle contraction.Multiple choice question.gatingrelaxationcontractioncoupling
Which of the following events in muscle contraction is the last to occur chronologically? The T-tubules depolarize, causing calcium to be released from the sarcoplasmic reticulum. Calcium is taken up into the sarcoplasmic reticulum. Tropomyosin moves, exposing the actin active sites. ATP binds to the myosin head allowing it to release from actin.
During contraction of a muscle, calcium ions bind to ______ which moves _______ out of the way. This now uncovers binding sites on the __________ myofilament. multiple choice 1troponin; tropomyosin; myosintroponin; tropomyosin; actintropomyosin; troponin; myosintropomyosin; troponin; actin 2. What molecules are attached to the myosin head from the previous cycle of movement? multiple choice 2ATP and phosphateADP and phosphateATP and calcium ionsADP and calcium ions 3. What is released in the process of cross-bridge formation? multiple choice 3ADPPhosphateATPCalcium ions 4. When the myosin head is moved, what is released (from the myosin head)? multiple choice 4ATPADPPhosphateCalcium ions 5. After the myosin head returns to its upright position, what occurs if calcium ions are still present? multiple choice 5Actin myofilaments move away from the M line.The entire sequence is repeated.Troponin blocks the binding sites on actin.Myosin heads will no longer bind to actin.
Which of the following happens as actin and myosin filaments slide past each other during muscle contraction?
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