Question

Muscle contraction occurs in a cyclic process. Which of the following sequences is in the correct order?power stroke, cross bridge formation, cross bridge dissociation, cocking of myosincross bridge formation, power stroke, cross bridge dissociation, cocking of myosincross bridge formation, cross bridge dissociation, cocking of myosin, power strokecross bridge formation, power stroke, cross bridge dissociation, power stroke, cocking of myosincross bridge formation, cocking of myosin, power stroke, cross bridge dissociation

Answer 1

cross bridge formation, power stroke, cross bridge dissociation, cocking of myosin

Step-by-step explanation:

The signal for the beginning of muscle contraction is acetylcholine (Ach) released from the presynaptic cell which then binds to its receptor on the muscle cell. This event causes depolarization and consequently the release of Ca ions from the sarcoplasmic reticulum. Ca helps the formation of actin-myosin cross bridge. The movement of myosin heads causes the move of actin and this process is called power stroke. In the absence of ATP, the myosin head will not detach from actin(ATP binding causes the myosin head to detach from the actin and causes cross bridge dissociation). Energy released form the ATP hydrolysis changes the myosin head into a cocked position.