試題詳解

15. Which of the following occurs when a skeletal muscle fiber contracts?
(A) The myosin head is bound to ATP.
(B) The myosin tail binds to actin, forming a cross-bridge.
(C) Releasing ADP and Pi, myosin fixes the thin filament.
(D) The tropomyosin is activated by ATP hydrolysis.
(E) Ca+2 entry into sarcoplasmic reticulum.