Multiple Choice
What is the functional unit of muscle contraction?
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9. Muscle Tissue
Sliding Filament Theory and the Sarcomere
Multiple Choice
Which two proteins slide past each other in the sliding filament theory of muscle contraction?
A
Tropomyosin and Troponin
B
Myosin and Troponin
C
Actin and Myosin
D
Actin and Tropomyosin
Verified step by step guidance1
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 sarcomere, the functional unit of a muscle fiber.
Identify the key proteins involved: The primary proteins that interact during muscle contraction are actin and myosin. Actin is a thin filament, while myosin is a thick filament.
Recognize the role of myosin: Myosin heads bind to specific sites on the actin filaments, forming cross-bridges. This interaction is crucial for the sliding mechanism.
Understand the sliding mechanism: Once the cross-bridges are formed, the myosin heads pivot, pulling the actin filaments toward the center of the sarcomere. This action is powered by ATP hydrolysis.
Differentiate from other proteins: Tropomyosin and troponin are regulatory proteins that control the access of myosin to actin binding sites, but they do not slide past each other during contraction.
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