Question

You have a strange disorder in which the myosin molecules are switched end to end. Comment on how this switch will influence the development of muscle tension. Defend your answer.

Answer 1

The cross bridge mechanism of muscle contraction occurs as follows,

1. Calcium ions bind to troponin and the active site on actin is exposed.
2. The myosin head forms cross bridge with actin.
3. The power stroke occurs and the myosin head bends releasing ADP and phosphate.
4. A new molecule of ATP attaches to myosin head causing the cross bridge to detach.
5. ATP hydrolyses to ADP and phosphate and the myosin head returns to the cocked position.

So, considering the above mechanism of development of muscle tension, even if the myosin molecules are switched end to end, there won't be any difference in the development of muscle tension as long as active site on actin is available.