Which of the following option correctly defines the function of sodium-potassium pump?

Options

A. `Na^(+)` and `K^(+)` out of the neuron
B. `Na^(+)` and `K^(+)` into the neuron
C. `Na^(+)` into the neuron and `K^(+)` out of the neuron
D. `K^(+)` into the neuron and `Na^(+)` out of the neuron

Answer

To solve the question regarding the function of the sodium-potassium pump, we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding the Sodium-Potassium Pump**:
- The sodium-potassium pump is a membrane protein that actively transports sodium (Na⁺) and potassium (K⁺) ions across the cell membrane.
- This pump is crucial for maintaining the resting membrane potential of neurons and other cells.

2. **Mechanism of Action**:
- For every three sodium ions that are transported out of the neuron, two potassium ions are transported into the neuron.
- This process requires energy, typically in the form of ATP, because it is moving ions against their concentration gradients.

3. **Concentration Gradients**:
- In a typical neuron at rest, sodium ions are more concentrated outside the cell, while potassium ions are more concentrated inside the cell.
- The pump helps to maintain these gradients, which are essential for the generation of action potentials and overall cellular function.

4. **Evaluating the Options**:
- **Option A**: Sodium and potassium out of the neuron - Incorrect, as only sodium is moved out.
- **Option B**: Sodium and potassium into the neuron - Incorrect, as only potassium is moved in.
- **Option C**: Sodium into the neuron, potassium out of the neuron - Incorrect, as sodium is moved out.
- **Option D**: Potassium inside the neuron and sodium out of the neuron - Correct, as it accurately describes the function of the pump.

5. **Conclusion**:
- The correct answer is **Option D**: Potassium inside the neuron and sodium out of the neuron.