Fundamentholfundamenthol
NEET2018Paper 2018Biology
Q.

. Calcium is important in skeletal muscle contraction because it

  1. A

    Binds to troponin to remove the masking of active sites on actin for myosin.

  2. B

     Detaches the myosin head from the actin filament.

  3. C

    Activates the myosin ATPase by binding to it.

  4. D

    Prevents the formation of bonds between the myosin cross bridges and the actin filament.

Solution

 Signal for contraction increase Ca++ level many folds in the sarcoplasm.

 Ca++ now binds with sub-unit of troponin (troponin "C") which is masking the active site on actin filament and displaces the sub-unit of troponin.

 Once the active site is exposed, head of the myosin attaches and initiate contraction by sliding the actin over myosin.

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