Final answer:
The equilibrium potential for chloride (Eāāā) will change according to the Nernst equation when the intracellular chloride concentration is 90 mM, affecting membrane potential and cellular excitability.
Step-by-step explanation:
The question relates to what happens to the equilibrium potential for chloride ions (ECl) when the intracellular chloride concentration is 90 mM.
In biological systems, the ECl can be determined using the Nernst equation. Chloride ions (Cl-) tend to accumulate outside of the cell due to the electrical gradient generated by the sodium-potassium pump, which moves two K+ ions into the cell while removing three Na+ ions, thus maintaining a negative charge inside the cell. As intracellular concentration of an ion changes, it will impact ECl because ECl is reflective of the balance of chloride across the cell membrane. If intracellular chloride concentration increases, it will shift the equilibrium potential according to the Nernst equation, which may lead to changes in membrane potential and cellular excitability.