Question

The ion required for muscle contraction and nerve impulse transmission is:

• A. ${\mathrm{Ca}}^{2+}$
• B. ${\mathrm{Mg}}^{2+}$
• C. ${\mathrm{Na}}^{+}$
• D. ${\mathrm{Ca}}^{2+}$ and ${\mathrm{Na}}^{+}$

Answer 1

The correct option is D ${\mathrm{Ca}}^{2+}$ and ${\mathrm{Na}}^{+}$

To enable muscle contraction, tropomyosin must change conformation and uncover the myosin-binding site on an actin molecule, thereby allowing cross-bridge formation. Troponin, which regulates the tropomyosin, is activated by calcium.

An action potential, also called a nerve impulse, speeds along an axon in milliseconds. Sodium ions flow in and cause the action potential, and then potassium ions flow out to reset the resting potential of the axon.

So the ion required for muscle contraction and nerve impulse transmission is ${\mathrm{Ca}}^{2+}$ and ${\mathrm{Na}}^{+}$ respectively.