BIOL 031 Lecture Notes - Lecture 16: Neuromuscular Junction, Nicotinic Acetylcholine Receptor, Skeletal Muscle

• School: College of The Sequoias
• Department: Biology (BIOL)
• Course: BIOL 031
• Professor: carey

Document Summary

Lec describe the four steps in the cross-bridge cycle, highlighting the roles of atp (hint: there are two of em) Resting state: myosin head is considered energized and has adp and pi attached; perpendicular to thick filament and energized through hydrolysis. Start: step 1 myosin binds to actin: ca2+ increases (sarcoplasmic reticulum releases ca2+) myosin head binds to thin filament. Ca2+ binds to troponin and moves tropomyosin out of the way. Step 2: power stroke: myosin-actin binding triggers release of pi and. Conformational chane of the myosin head that pulls the thin filament towards the center of the sarcomere each powerstroke is. Step 3: release: the cross bridge is broken down when atp binds to myosin head and if no atp is present then the myosin head stays bound. Step 4: re-cocking: the enzyme myosin atpase splits the atp into. Myosin head returns to energized confirmation to bind actin again and continue the cycle.