Question

The metal ion, that plays an important role in muscle contraction is:
A) $Be^{2+}$
B) $Mg^{2+}$
C) $Ca^{2+}$
D) $Ba^{2+}$

Answer 1

Hint: Muscle contraction is the process by which the tension generating sites within the muscle fibres gets activated. All the types of muscle including smooth, cardiac and skeletal undergoes contraction. The muscle contraction is regulated by ion which is abundantly found in the body as the chief constituent of bones and teeth.

Complete answer:
The muscle contraction means tightening or shortening of muscles. The muscles are made up of actin and myosin filament. The muscle contraction takes place when the actin and myosin filament slide over each other. For muscle contraction, a stimulus is generated from a nerve cell which directs the actin and myosin and leads to contraction. For example, the motor neurons stimulate the muscle fibres in the arms and shoulder which lead to contraction as a result of which movement of arm is facilitated.

Steps for muscle contraction:
1)The contraction of muscles takes place by the release of calcium ion from the SR terminal.
2)The Myosin head binds to the actin binding site.
3)The ATP is hydrolysed resulting in release of ADP and Pi.
4)The ATP helps in releasing the Myosin head.
5)The ATP is hydrolysed which re-energizes the Myosin head.
6)The calcium is pumped back into the SR terminal.

Hence, the correct answer is option (C)

Note: Calcium is very much essential for the human body. It is essential for bones and teeth. It is an important factor in blood clotting. It also facilitates transmission of nerve impulses, maintains fluid balance in the body and also regulates our heart beat.