Active Sites on the Actin Become Available for Binding After

Question

Active sites on the actin become available for binding after
A) actin binds to troponin.
B) troponin binds to tropomyosin.
C) calcium binds to troponin.
D) calcium binds to tropomyosin.
E) myosin binds to troponin.

Accepted Answer

Calcium binds to troponin, causing a conformational change that moves tropomyosin away from the active sites on actin, allowing myosin to bind to actin and initiate muscle contraction. Troponin does not directly bind to actin and myosin does not bind to troponin.