Bio hw
Updated: 5/18/2020
Bio hw

Storyboard Text

  • Hey! It’s starting to rain! We should probably go home now.
  • Yea your probably right, let’s run!
  • Hey so I was wondering, how does muscle contraction work when we run?
  • So, There are thick filaments (Myosin) that are anchored on the M line and thin filaments (Actin) anchored on the Z line. A Contraction begins when ATP is hydrolyzed into ADP causing Myosin to extend
  • Oh wow! Then what?
  • When an action potential is reached in a striated muscle cell, the sarcoplasmic reticulum releases Calcium ions into the myofibrils. and Calcium binds on Actin.
  • ok, then?
  • Actin contains many protein “pearls” linked together. In addition, Actin's two protein fibers Troponin and Tropomyosin connected to it respond to the presence of Ca+2. Troponin binds to Ca+2, which moves Tropomyosin which moves to create binding sites.
  • And then the myosin head now can attach to Actin at the cross bridge, and triggering a power stroke. The energy stored in the myofilament causes pulling of the filament towards the M line, shortening the Sarcomere and releasing ADP!
  • yea see you get it!
  • Lastly, myosin and actin remain attached until ATP attaches once again, breaking the bond at the cross bridge. This frees myosin making it possible for another contraction or to relax.
  • Oh cool! your really smart!