How does the increase in calcium ion level lead to muscle contraction?

How does the increase in calcium ion level lead to muscle contraction?
  1. By increasing the cross-bridge formation between actin and myosin
  2. By binding with a subunit of troponin on actin filaments and thereby removing the masking of active sites for myosin
  3. By causing the return of ‘Z’ lines back to their original position
  4. By pumping calcium ions back to the sarcoplasmic cisternae

Solution

Increase in Ca²⁺ level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby remove the masking of active sites for myosin.

Asked in: NCERT

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