Question

Which of the following is responsible for maintaining low \(Na^{+}\) and high \(K^{+}\) concentrations in the cell relative to the extracellular fluid?

• A. Na$^+$K$^+$ ATPase
• B. Na$^+$ channel
• C. $K^{+}$ channel
• D. Both $Na^{+}$ and $K^{+}$ channel

Hint:

Pump = Energy = Against the gradient. Channels = Open doors = With the gradient.

Answer 1

The Correct Option is A

Step 1: Concept
Cells must maintain specific ion gradients to function properly.

Step 2: Meaning
Maintaining a gradient against the natural flow of diffusion requires active transport using energy.

Step 3: Analysis
Ion channels allow ions to move passively down their concentration gradient. The $Na^{+}/K^{+}$ ATPase uses ATP to actively pump $Na^{+}$ out and $K^{+}$ in, maintaining low sodium and high potassium inside the cell.

Step 4: Conclusion
The $Na^{+}/K^{+}$ ATPase is the primary active transporter responsible for this gradient.

Final Answer: (A)