How does tropomyosin control muscle contraction?
A) It provides a bridge between actin and myosin.
B) It provides a site where ATP can be utilized.
C) Changes in its position expose myosin-binding sites on actin filaments.
D) It transmits electric charge to the filaments.
E) Changes in its shape cause membrane channels to open.

Question

Quizplus · Accepted Answer

Tropomyosin controls muscle contraction by regulating the exposure of myosin-binding sites on actin filaments. When calcium ions bind to the troponin complex, it causes a conformational change in tropomyosin, exposing the myosin-binding sites and allowing for cross-bridge formation between actin and myosin, leading to muscle contraction. Without this regulation, the muscle fibers would remain in a contracted state.

How Does Tropomyosin Control Muscle Contraction