Skeletal Muscle Contraction Begins When Calcium Ions Bind To

Question

Skeletal muscle contraction begins when calcium ions bind to
A) energized cross-bridges.
B) myosin.
C) actin.
D) tropomyosin.
E) troponin.

Accepted Answer

Skeletal muscle contraction is initiated when calcium ions bind to troponin, which causes a conformational change in the protein complex and exposes the active sites on the actin filaments. This allows the myosin heads to attach to the actin and begin the sliding filament mechanism of muscle contraction.