NEET 2018, Biology Q87: Muscle

NEET2018Paper 2018Biology

. Calcium is important in skeletal muscle contraction because it

A
Binds to troponin to remove the masking of active sites on actin for myosin.
B
Detaches the myosin head from the actin filament.
C
Activates the myosin ATPase by binding to it.
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.

Concept behind this question

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