At the conclusion of the power stroke a actin has been moved

At the conclusion of the power stroke,

a) actin has been moved toward the M line.

b) the myosin head is tightly bound to actin.

c) inorganic phosphate has been released from the myosin.

d) ADP is released from the myosin head.

e) All of the above

Solution

Option E all of the above is the correct answer.

The power stroke occurs at the release of phosphate from the myosin molecule after the ATP hydrolysis while myosin is tightly bound to actin. The effect of this release is a conformational change in the molecule that pulls against the actin. The binding of a new ATP molecule will release myosin from actin. ATP hydrolysis within the myosin will cause it to bind to actin again to repeat the cycle.