객관식
What is the area in the center of the A band where there are no actin myofilaments?
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9. Muscle Tissue
Sliding Filament Theory and the Sarcomere
객관식
In the sliding filament theory, what substance causes the actin filament to change shape, allowing myosin to bind?
A
ATP
B
Calcium ions
C
Potassium ions
D
Sodium ions
검증된 단계별 안내1
Understand the sliding filament theory: This theory explains how muscles contract by the sliding of actin and myosin filaments past each other, which shortens the muscle fiber.
Identify the role of calcium ions: Calcium ions play a crucial role in muscle contraction by binding to troponin, a regulatory protein associated with the actin filament.
Explain the effect of calcium binding: When calcium ions bind to troponin, it causes a conformational change in the troponin-tropomyosin complex, exposing the binding sites on actin for myosin.
Recognize the importance of this interaction: The exposure of binding sites on actin allows myosin heads to attach, forming cross-bridges, which is essential for muscle contraction.
Differentiate between the substances: While ATP is necessary for the energy required for muscle contraction, calcium ions are specifically responsible for the change in shape of the actin filament, allowing myosin binding.
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