Topic 6 processes Flashcards
Stages of the sliding filament theory
1) When an action potential reaches a muscle it stimulates a response
2) Calcium ions enter and cause the protein tropomyosin to move and uncover the binding sites on actin
3) Whilst ADP is attached to the Myosin head, the myosin heads bind to the actin to form a cross bridge
4) The angle created in this cross bridge creates tension and the actin filament is pulled and slides along the myosin. In doing so, the ADP molecules are released with Pi
5) An ATP molecule then binds to the myosin head and causes it to change shape slightly. As a result, it detaches from the actin
6) Within the sarcoplasm, there is the enzyme ATPase, which is activated by the calcium ion to hydrolyse the ATP on the myosin head to return to its original position
7) The entire process repeats continually whilst the calcium ions remain high, and therefore the muscle remains stimulated by the nervous system
