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When a muscle is at rest the active sites on the actin are blocked by?
Wiki User
∙ 12y ago
TROPOMYOSIN MOLECULES ( troponin hold the tropomyosin in place)
Wiki User
∙ 12y ago
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When the sarcomere is at rest what is covering the active sites on actin?
Troponin
Myosin cross bridges attach to active sites of?
actin (thin) filaments
ADP molecules on the surface of actin serve as active sites for the formation of cross bridges with molecules of?
ATP not ADP binds to actin-myosin and is cleaved by to ADP.
What does sarcoplasmic reticulum do?
The Sarcoplasmic Retiulum releases calcium ions that will cause troponin/tropomyosin complex to move. This exposes the binding sites on actin and allows the cross-bridges of myosin to bind to the actin binding sites.
What is the role of tropomyosin in muscles?
Tropomyosin is the thick filament of a muscle sarcomere. It lines the span of 7 G-actin monomers along the grooves of the F-actin filament. Troponin is a trimer that consists of subunits TN-C, TN-I and TN-T. Troponin is attached to tropomyosin and its function is involved in muscle contraction. In a powerstroke of a muscle contraction you have TN-I blocking the myosin head from attaching to the myosin binding site on the actin filament. This is the resting state. When you contract your muscles, calcium is released and attaches to TN-C. This produces a conformational change that moves TN-I away from the myosin head. In turn the myosin binds to the myosin binding site. On the myosin head there is a myosin ATPase that hydrolyzes an ATP which provides the energy for the head to bend 45 degrees. This is the powerstroke that produces muscle contraction. Another ATP molecule will enter in and release the myosin head and calcium is pumped back into the sarcoplasmic reticulum. The resting state is restored!
During muscle contraction myosin cross bridges attach to which active sites?
actin filaments
What is the protein that regulates muscle contraction by controlling the availability of active sites on actin called?
tropomyosin
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 does myosin attach to?
During muscle contraction, myosin cross bridges attach to active sites of ACTIN FILAMENTS.
When the sarcomere is at rest what is covering the active sites on actin?
Troponin
Active sites on the actin become available for binding when?
C: Calcium binds to troponin. The troponin is a filament in the actin strand, and the active site needs to be uncovered so that the myosin head can bond and therefore pull the muscle to contract it.
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.
Myosin cross bridges attach to active sites of?
actin (thin) filaments
What muscle cell protein covers the myosin binding sites on actin fimlaments?
tropomyosin
Binding sites on the actin molecules are covered by troponin and?
muscle that produces a give movement
ADP molecules on the surface of actin serve as active sites for the formation of cross bridges with molecules of?
ATP not ADP binds to actin-myosin and is cleaved by to ADP.
What blocks a bonding site in muscle?
Several things do. Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction causing paralysis. Quaternary ammonium muscle relaxants are quaternary ammonium salts used as drugs for muscle relaxation, most commonly in anesthesia.When a muscle is in a resting state, actin and myosin are separated. To keep actin from binding to the active site on myosin, regulatory proteins block the molecular binding sites. Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle without nervous input.Several things do. Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction causing paralysis.Quaternary ammonium muscle relaxants are quaternary ammonium salts used as drugs for muscle relaxation, most commonly in anesthesia.Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle without nervous input.
