Question

The most abundant intracellular cation is?

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

Answer 1

The correct option is C

${\mathrm{K}}^{+}$

The correct option is C.

Explanation of the correct answer:

1. ${\mathrm{K}}^{+}$ is the most abundant intracellular cation involved in nerve conduction and maintenance of membrane potential.
2. It is also required for muscle contraction.
3. Also, plants require ${\mathrm{K}}^{+}$ for stomatal opening and closing activities. During photosynthesis, potassium is transported from the epidermal cell to the guard cell in order for the stomata to open and close.
4. It also helps in fluid and electrolyte balance.

Explanation of the incorrect options:

Option A:

1. The concentration of ${\mathrm{Ca}}^{+2}$ is very less in the intracellular fluid.
2. Hence it is an incorrect option.

Option B:

1. The ${\mathrm{Na}}^{+}$ is present in the largest concentration in the extracellular fluid, not the intracellular.
2. Hence, it is an incorrect option

Option D:

1. The ${\mathrm{H}}^{+}$ concentration is also not large as it is found only in aqueous solutions of all acids.
2. Hence, it is an incorrect option.

Final answer: The most abundant intracellular cation is ${\mathrm{K}}^{+}$