Question

Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction
A. Sodium
B. Potassium
C. Calcium
D. Magnesium

Answer 1

Calcium is the ion that is discharged into the sarcoplasm from the sarcoplasmic reticulum during the process of polarisation. $C{a^{ + + }}$ fastens to the Troponin-C. This step gives rise to a confirming change in the tropomyosin. As an outcome of the unmasking of active sites on actin for myosin takes place. Cross bridges are constructed between actin and myosin. This concludes in muscle contraction.

Complete answer:

Option-A Sodium is a chemical element with the scientific symbol Na and its atomic number is 11. It is a soft, silvery-white, highly reactive metal. Sodium is said to be an alkali metal, being in group 1 of the periodic table. P The free metal does not exist in nature, and it must be educated from compounds.
Option-B: Potassium is a chemical component with the scientific symbol K and atomic number 19. Potassium is a silvery-white metal that is soft sufficient to be cut with a knife along with little force. Potassium metal that responds rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure.
Option-C: Calcium is a mineral that is essential for life. In addition to building bones as well as keeping them healthy, calcium enables our blood to clot, our muscles to contract, along with it helps our heart to beat. About 99% of the calcium present in our bodies is in our bones and teeth.
Option-D - Magnesium is a chemical element with the scientific symbol as Mg and atomic number 12. It is a shiny grey solid that bears a close physical resemblance to the other five elements that us in the second column of the periodic table.

So, the right answer to the provided question is option – C “Calcium”.

Note:
In striated muscle, calcium causes a shift in the posture of the troponin complex on actin filaments, that is exposed to myosin-binding sites. Myosin scamper by ADP as well as inorganic phosphate (Pi) can then form cross-bridges with actin, along with the discharge of ADP and Pi generates the power stroke that drives muscle contraction.