Which of the following statements is correct?
A) Tropomyosin molecules move and expose specific sites on myosin filaments.
B) Actin filaments slide along myosin filaments.
C) Cross-bridges form between actin and the sarcolemma.
D) Filaments of troponin and tropomyosin slide past one another.

Question

Quizplus · Accepted Answer

The sliding filament theory of muscle contraction states that actin filaments slide along myosin filaments, pulling the Z-lines closer together and causing the muscle to contract. Option A is incorrect because tropomyosin molecules do not move, but rather block or expose specific binding sites on actin filaments. Option C is incorrect as cross-bridges form between actin and myosin filaments, not the sarcolemma. Option D is also incorrect as filaments of troponin and tropomyosin do not slide past one another, but rather work together to regulate muscle contraction by exposing or covering binding sites on actin filaments.

Which of the Following Statements Is Correct