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Which step allows actin and myosin to release from each other?
an ATP molecule attaches to myosin apex answers
What is the role of tropomyosin in muscles?
The troponin-tropomyosin complex changes shape and sinks deeper into the groove of the thin filaments. This exposes the active sites of the actin filaments and makes them available for binding to myosin heads.
What region in a sarcomere does actin and myosin overlap?
The region in a sarcomere where actin and myosin overlap is called the A band. This is where the thick myosin filaments and thin actin filaments interact to generate muscle contraction.
Sliding filament model which proteinS have a calcium binding site?
In the sliding filament model of muscle contraction, the protein troponin has a calcium binding site on the troponin C subunit. When calcium binds to troponin C, it triggers a conformational change in the troponin-tropomyosin complex, allowing myosin heads to interact with actin and initiate muscle contraction.
Does myosin have the ability to swivel when powered by ATP?
Yes...ATP causes myosin to detach from actin. Then, Hydrolysis of ATP, which results in ADP and P, causes conformational change in myosin head to swivel or pivot about its axis and then weakly bind to an actin filament. Once the myosin head binds, a conformational change in the myosin head will cause the P to leave (the ADP is still stuck on). The leaving of the P causes the power stroke or "the pulling of the actin filament/rowing stroke". ADP then leaves and the myosin is now back at its original state.
Which myofilament has a binding site for myosin head?
The myofilament that has a binding site for the myosin head is actin. Actin filaments contain specific regions known as binding sites that interact with the myosin heads during muscle contraction. This interaction is crucial for the sliding filament theory, where the myosin heads pull the actin filaments to shorten the muscle fiber. The binding of myosin to actin is regulated by the presence of calcium ions and the protein tropomyosin.
Binding of the myosin heads sequentially prevents what?
myosin crossbridge binding
Which event causes cross bridge detachment?
The binding of ATP to the myosin head causes cross bridge detachment by disrupting the binding between myosin and actin. ATP provides the energy necessary for myosin to release from actin and reset for the next contraction cycle.
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 binding of the myosin heads sequentially prevent?
Binding of the myosin heads sequentially prevents the actin-binding sites on the thin filaments from becoming continuously occupied by myosin heads, allowing for the muscle fiber to relax and the sarcomere to lengthen.
How do proteins actin and myosin interact to make a muscle contract?
Myosin and Actin
How does an increase in intracellular calcium cause a muscle fiber to contract?
An increase in intracellular calcium concentration triggers muscle contraction by binding to troponin, a regulatory protein on the actin filaments. This binding causes a conformational change that moves tropomyosin away from the myosin-binding sites on actin, allowing myosin heads to attach to actin. The myosin heads then pivot, pulling the actin filaments inward and resulting in muscle contraction through the sliding filament mechanism. Ultimately, this process is regulated by the calcium levels within the muscle fiber.
What specifically is cross bridge?
myosin binding to actin
What immediately follows the binding of ATP to the myosin head?
The myosin head pivots, moving the actin strand.
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.
What protein interact in muscle cells?
Actin and myosin interact in muscle cells.
What protein shields the myosin-binding site preventing contraction from happening at rest?
ATP entering myosin head
