Potential difference across resting membrane is negatively charged. This is due to differential distribution of the following ions.

Options

A. `Na^+ & K^+ ` ions
B. `CO_(3++) & Cl^- ions
C. `Ca^(++) & Mg^(++) ` ions
D. `Ca^(+4) & CL^- ions

Answer

To solve the question regarding the potential difference across a resting membrane being negatively charged due to the differential distribution of ions, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Resting Membrane Potential**:
The resting membrane potential is typically around -70 mV, indicating that the inside of the cell is negatively charged relative to the outside.

2. **Identifying Ion Distribution**:
The resting membrane potential is primarily influenced by the distribution of certain ions across the membrane. The key ions involved are sodium (Na⁺) and potassium (K⁺).

3. **Sodium Ion (Na⁺) Concentration**:
In a resting state, the concentration of sodium ions is higher outside the cell. This creates a positive charge in the extracellular fluid.

4. **Potassium Ion (K⁺) Concentration**:
Conversely, the concentration of potassium ions is higher inside the cell. This contributes to the negative charge inside the cell.

5. **Role of Negatively Charged Proteins**:
Additionally, the presence of negatively charged proteins inside the cell further contributes to the negative charge of the resting membrane potential.

6. **Conclusion**:
Therefore, the differential distribution of sodium ions (higher outside) and potassium ions (higher inside) is responsible for the negative resting membrane potential.

### Final Answer:
The potential difference across the resting membrane being negatively charged is due to the differential distribution of sodium ions (Na⁺) and potassium ions (K⁺).