BIOL 207 Study Guide - Final Guide: Axon Terminal, Myosin Head, Axon
Document Summary
Mechanism of muscle contraction: sliding filament mechanism (sfm: myosin cross bridge (x-bridge) activity. When moved aside, actin and myosin can bind: myosin head has 2 binding sites: actin binding site & atp binding site. Actin binding site: part of cross bridge that connects to actin. Atp attaches to cross bridge, cross bridge has atpase atp is split (adp + pi [phosphate]) When splitting energy is released, energy reconfigures angle of cross bridge cocked (energized) state: a-m i complex. Actinmyosin i: a high energy, unstable, and short-lived complex: power stroke. When cross bridges attach, energy released and cross bridges pull actin toward the middle. At end of inner swiveling [power stroke] a-m i a-m ii: a-m ii complex (rigor complex) Actinmyosin ii: very stable, potentially long lived, low energy: role of atp in x-bridge cycle detachment from the actin and re-cocking the cross bridge, etc. Atp attaches to cross bridge and when splits releases energy cocks cross bridge.
