17. List and describe the event of muscle contraction at the level of the myosin head attachment at actin.

List and describe the event of muscle contraction at the level of the myosin head attachment at actin. Part 1

1. In the attachment step, the myosin head binds tightly to the actin filament

List and describe the event of muscle contraction at the level of the myosin head attachment at actin. Part 2

2. In the next step, ATP is bound, reducing myosin's affinity for actin, releasing its attachment.

List and describe the event of muscle contraction at the level of the myosin head attachment at actin. Part 3

3. After the hydrolysis of ATP to ADP & Pi, there is a conformational change in the myosin head to the cocked position, which positions the myosin head laterally to bind to the next binding site on the actin filament.

List and describe the event of muscle contraction at the level of the myosin head attachment at actin. Part 4

4. Weak binding of the myosin head releases the Pi causing another conformational change which creates tight binding and generates force called the power stroke. The causes the filaments to shift overall causing a slight contraction of the sarcomere.

List and describe the event of muscle contraction at the level of the myosin head attachment at actin. Part 5

5. After the power stroke, the myosin head is not back to the original attachment position where the process will continue until the sarcomere is fully contracted.