What Is a Cross-Bridge

Multiple Choice

What is a cross-bridge?

A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O₂ taken in that exceeds the O₂ required for resting metabolism