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Cross bridges are formed during muscle contraction when the myosin heads of thick filaments attach to binding sites on the actin filaments of thin filaments. This interaction occurs when calcium ions are released, leading to a conformational change in the troponin-tropomyosin complex that exposes the binding sites on actin. Once the myosin heads bind to actin, they pivot and pull the actin filaments inward, resulting in muscle shortening and contraction. This process is powered by ATP hydrolysis, which re-cocks the myosin heads for another cycle of cross-bridge formation.
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During skeletal muscle contraction myosin cross bridges attach to active sites of?
During skeletal muscle contraction myosin cross bridges attach to active sites of actin filaments. Actin filaments bind ATP. Their growth is regulated by thymosin and profilin.
During muscle contraction myosin cross bridges attach to which active sites?
actin filaments
Myosin cross bridges attach to active sites of?
actin filaments in muscle cells during muscle contraction.
What does myosin attach to?
During muscle contraction, myosin cross bridges attach to active sites of ACTIN FILAMENTS.
Where are the cross bridges involved in muscle contraction?
in the terminal cisternae
What is the time in which cross bridges are active called?
The time in which cross bridges are active during muscle contraction is called the "cross-bridge cycle." This cycle involves the binding of myosin heads to actin filaments, power stroke generation, and detachment of the cross bridges.
When myosin cross bridges bind to actin what happens?
Muscle contraction results
What best describes the events of excitation in excitation-contraction coupling?
cross bridge formation "Excitation-contraction coupling" connects muscle fiber excitation to the muscle fiber contraction (cross bridge formation). During contraction, myosin heads form cross bridges many times-with each cross bridge generating a small amount of tension in the muscle fiber.
What acts as ATPase during the contraction cycle of muscle?
myosin cross-bridges
Does the Z line shorten during muscle contraction?
Yes, the Z line shortens during muscle contraction.
The muscle decreases in muscle length during contraction but tension is the same?
Isotonic contraction
Which muscle protein forms cross-bridges?
The muscle protein that forms cross-bridges is myosin. Myosin molecules have a head region that binds to actin filaments, enabling muscle contraction through the sliding filament mechanism. When myosin heads attach to actin, they pivot, pulling the actin filaments closer together, which shortens the muscle fiber and generates force. This interaction is crucial for muscle contraction during activities such as movement and posture maintenance.
