PHYSIOLOGY
SYNAPTIC PHYSIOLOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
On myosin
|
|
|
On actin
|
|
|
Along the sarcolemma
|
|
|
They are alone
|
Detailed explanation-1: -Troponin and tropomyosin are two proteins that are present on the thin filaments of the muscle cells and help in the contraction of muscles.
Detailed explanation-2: -Each troponin–tropomyosin complex contains four distinct polypeptides: tropomyosin and the three proteins of the troponin complex (TnI, TnT, and TnC). Tropomyosin (molecular mass of 66 kDa) lies in the long pitched grooves on either side of the actin filament and is thought to act as a “stiffener” for the filament.
Detailed explanation-3: -Tropomyosin, a long coiled-coil alpha-helical molecule, is located in each of the two long-pitch helical grooves of actin, but troponin, a globular molecule, is attached at intervals of 38 nm (refs 1, 2).
Detailed explanation-4: -Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction.
Detailed explanation-5: -The protein complex troponin binds to tropomyosin, helping to position it on the actin molecule.