The sliding filament theory of how a skeletal muscle contracts involves the activities of 5 different molecules plus calcium ions?
What is the SLIDING FILAMENT THEORY?
It is the process of muscle contraction involving the sliding of actin & myosin myofilaments past each other to shorten the length of each sacromere.
What are the 6 steps of SINGLE CROSS BRIDGE CYCLING?
1.The influx of calcium, triggering the exposure of the binding sites on actin.
2.The binding of myosin to actin.
3.The power stroke of the cross bridge that causes the sliding of the thin filaments.
4.The binding of ATP to the cross bridge, which results in the cross bridge disconnecting from actin.
5.The hydrolysis of ATP, which leads to re-energizing & repositioning of the cross bridge.
6.The transport of calcium ions back to the SR.
An ___brings about the release of calcium ions from the _______.
-Terminal cisternae of the SR
Calcium ions flood into the cytosol & _____, causing a ________of the troponin-tropomyosin complex.
This conformation change ____the binding sites on ____.
-Bind to the troponin
-Change in conformation
The binding of myosin to actin brings about a _____ of the cross bride, resulting in the release of ___&___.
At the same time, the cross bridge ___, pulling the ____inward toward the _____. This movement is called the "_____."
The _____has been transformed into the ____of contraction.
-Change in the conformation
-ADP & P(i)
-Center of the sacromere
-Chemical energy of ATP
The release of the myosin cross bridge from actin triggers the ____of the ATP molecule into ___&___.
-ADP & P(i)
Calcium is _____from the cytosol into the ____by ____.
As the calcium is removed, the troponin-tropomyosin complex again ____the binding sites on ____.