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What ion initiates muscle contraction?
Calcium ions initiate muscle contraction by binding to the protein complex known as troponin, which then causes a conformational change in the protein tropomyosin. This conformational change exposes the active sites on actin filaments, allowing myosin cross-bridges to bind and initiate the muscle contraction process.
What is the relationships between cellular respiration muscle contraction and rigor mortis?
Cellular respiration in muscle cells produces ATP, which is essential for muscle contraction. After death (rigor mortis), ATP production stops, leading to a lack of energy for muscle relaxation. This causes muscles to stiffen due to an inability to break the cross-bridges between actin and myosin filaments.
Myosin contains two binding sites for what two molecules?
ATP (--> ADP+Pi) and actin
What happens during skeletal muscle contraction?
During skeletal muscle contraction, motor neurons activate muscle fibers, causing calcium ions to be released from the sarcoplasmic reticulum. The calcium ions bind to troponin, leading to the exposure of active sites on actin filaments. Myosin heads then attach to these active sites, form cross-bridges, and pull the actin filaments towards the center of the sarcomere, resulting in muscle contraction.
What is the function of calcium ions in skeleal muscle contraction'?
Calcium ions play a crucial role in skeletal muscle contraction by initiating the process of muscle fiber contraction. When a muscle is stimulated, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm. These calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from binding sites on actin filaments. This exposure allows myosin heads to attach to actin, facilitating the cross-bridge cycle that leads to muscle contraction.
When myosin cross bridges bind to actin what happens?
Muscle contraction results
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.
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.
What is the function of troponin in muscle contractions?
It is involved in the regulation of the contraction of a cross-striated muscle.
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.
During muscle contraction myosin cross bridges attach to which active sites?
actin filaments
What describes the events of contraction 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.
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.
Cross-bridge formation that results in muscle contraction requires intracellular?
the major intracellular ion in crossbridge formation is what
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.
What acts as ATPase during the contraction cycle of muscle?
myosin cross-bridges
