BIOL 1412 Lecture Notes - Troponin, Myoglobin, Myosin Head

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 1412
• Professor: Paul Messing

Document Summary

Sliding filament mech: atp attaches to myosin head, causing its release from actin + unpivot = 9. 12: myosin head reactivates (atp adp +pi, if ca+2 in cytosol remains high these steps continue. Cycle repeats many times to shorten the sacromere (fig. A-band = same length: myofibrils shorten: 1) ach broken down by ache on motor end plate (facing cleft) (fig. Reticulum (sr) actively takes up ca+2 (ca+2 -atpase) 3) tropomyosin covers myosin binding sites on actin. 4) atp binds to and releases myosin heads (fig. Atp necessary for: crossbridge release (atp not broken down, activation of myosin (atp adp + pi, pump ca+2 into sr (fig. Prevent exocytosis of ach - flacaid paralysis. Medical - treat uncontrolled blinking, crossed eyes. = force exerted by a muscle or muscle fibre. = twitch (not normally occurring) i) 1 stim. 1 ap (lasts 1-2 msec. ) (similar to fig. Excitation - contraction coupling occurring iii) contraction period (10-100 msec. )