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What molecule has a binding site for myosin heads?
Myosin heads bind to the actin binding site, and also has a part where ATP binds
How does troponin facilitate cross bridge formation?
Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin.
What unmasks troponin protein?
Ca 2+ ions released from the sarcomeres ER bind to troponin and force a conformational change that opens the way for myosin to bind to actin.
What triggers the binding of myosin to actin?
Calcium ions bind to troponin and change its shape.
What are the proteins are involved in muscle contraction?
Actin and myosin
What specific event triggers the uncovering of the myosin site on actin?
Calcium ions bind to troponin and change its shape.
What blocks the myosin binding sites on the actin molecule preventing cross bridge formation?
The tropomyosin molecule blocks the active sites of the actin. Troponin is a molecule that is bound to the tropomyosin. Troponin needs CA+ (calcium ions) to bind to it in order to rotate the tropomyosin molecule and expose the actin molecules for the myosin heads to interact for muscle contraction.
The binding of calcium to which molecule causes the myosin binding sites to be exposed?
Troponin binds to the Calcium ions to expose the actin to the myosin heads.
What does calcium bind to in smooth muscle contraction?
Calcium binds to the messenger protein Calmodulin. The calcium-calmodulin complex then activates myosin light chain kinase (MLCK), which phosphorylates myosin to allow it to bind to actin - producing contraction.
What happens when calcium ions bind to troponin?
When Ca2+ ions are released from the sarcoplasmic reticulum, They combine with troponin, and this cause the tropomyosin threads to shift their position
How is calcium used in muscle contraction?
Calcium binds to troponin, which moves the tropomyosin out of the way so that myosin can bind to actin; this ultimately causes a power-stroke.
What mineral is needed to allow actin and myosin to interact?
In order for myosin to connect to actin's active sites, Ca ions must be released from storage in the sarcoplasmic reticulum into the sarcoplasm. A nerve impulse stimulates the release of Ca ions from the sarcoplasmic reticulum. Once the Ca ions are released into the sarcoplasm, they bind to troponin. Once they bind to troponin, troponin no longer is bound to tropomyosin. Tropomyosin is now no longer covering up actin's active sites, thus allowing myosin to attach to actin's active sites.
