NEET Solved Paper 2018 Question 78
Question: Calcium is important in skeletal muscle contraction because it [NEET - 2018]
Options:
A) Detaches the myosin head from the actin filament.
B) Activates the myosin ATPase by binding to it.
C) Binds to troponin to remove the masking of active sites on actin for myosin.
D) Prevents the formation of bonds between the myosin cross bridges and the actin filament.
Show Answer
Answer:
Correct Answer: C
Solution:
- Signal for contraction increase $ C{a^{++}} $ level many folds in the sarcoplasm. $ C{a^{++}} $ 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.
