The "Head" That Forms the Cross Bridge When the Muscle

Question

The "head" that forms the cross bridge when the muscle cell contracts is part of which protein?
A) actin
B) the thin filament
C) myosin
D) both A and B

Accepted Answer

The "head" that forms the cross bridge when the muscle cell contracts is part of the myosin protein. Actin and the thin filament are involved in muscle contraction, but they do not contain the specific structure known as the cross bridge.