Which among the following is not involved in the muscular contraction?
A
Ca ion
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Troponin
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
Actin
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Mg ion
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is A Mg ion
Active sites for myosin(Thick filament) are present on actin which are masked by troponin in resting state. when Ca++ level increases it leads to the binding of calcium with a subunit of troponin on actin(thin) filaments and thereby remove the masking of active sites for myosin.
Utilizing the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
This pulls the attached actin filaments towards the centre of ‘A’ band.
The ‘Z’ line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction.
magnesium acts as a natural calcium blocker to help muscles relax. Hence Mg ion is not involved in the muscular contraction but it is involved in muscle relaxation by blocking calcium ions.