True or false: The "power stroke" described during the cross-bridge formation refers to the myosin head pivoting when it combines with actin shortening the sarcomere.

Question

BlackTom AI · Accepted Answer

The question asks us to evaluate the statement about the so-called power stroke in muscle contraction.
Option 1: True. The power stroke refers to the pivotal conformational change of the myosin head that occurs after it attaches to actin and releases ADP. During this stroke, the myosin head rotates, pulling the actin filament toward the center of the sarcomere, which results in shortening of the sarcomere. This description aligns with the cross-bridge cycle's sequence, where binding to actin followed by the power stroke drives filament sliding and muscle contraction.
Option 2: False. If one were to claim that the power stroke does not shorten the sarcomere, or that it is not associated with the myosin actin interaction, this would conflict with the primary mechanism of sarcomere shortening. The power stroke is fundamentally about the myosin pivot that generates the sliding force; denying this would misrepresent the core idea that the cross-bridge cycle converts chemical energy from ATP into mechanical work that shortens the sarcomere.
In summary, the essence of the power stroke is the myosin head pivoting during a strong actin-myosin interaction, producing filament sliding and sarcomere shortening, which makes the described statement consistent with established muscle physiology concepts. The alternative interpretation would misstate the role of the power stroke or the relationship between myosin and actin during contraction.

BIOL 251 Module 5 Problem Set

True or false: The "power stroke" described during the cross-bridge formation refers to the myosin head pivoting when it combines with actin shortening the sarcomere.

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BIOL 251 Module 5 Problem Set

True or false: The "power stroke" described during the cross-bridge formation refers to the myosin head pivoting when it combines with actin shortening the sarcomere.

查看解析

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类似问题

Question at position 24 In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and __________. myosin actin tropomyosin troponin

A marathon runner started experiencing muscle cramps towards the end of the race. This is thought to be due to electrolyte loss. Which of the following is most critical for muscle contraction?

Application-Level Multiple-Choice Items​ Magnesium is an important mineral that works with calcium in the body to:​

The antagonist muscle(s) passively __lengthen __during the lifting phase and passively __shorten __during the lowering phase. To lift (or push or pull) a resistance the agonists are _concentrically __ contracting, to control the resistance back down the agonists are __eccentrically __ contracting.

更多留学生实用工具

希望你的学习变得更简单

Application-Level Multiple-Choice Items Magnesium is an important mineral that works with calcium in the body to:

The antagonist muscle(s) passively lengthen during the lifting phase and passively shorten during the lowering phase. To lift (or push or pull) a resistance the agonists are _concentrically contracting, to control the resistance back down the agonists are eccentrically __ contracting.