Question

Which of the following statements concerning cross bridges is incorrect

A. Cross bridges are globular heads of myosin molecules

B. Cross bridges have actin vining sites that are normally covered by troponin and tropomyosin except during excitatation- contraction coupling

C. Cross bridges bind with actin and then bend to pull the thin filaments inward during contraction according to the sliding filament mechanism

D. Mg2+ is necessary to bind ATP to the crops bridge

E. A fresh molecule of the ATP must be bound to the cross bridge to break the bond between actin and myosin