Final answer:
The dephosphorylated sodium-potassium pump has a high affinity for sodium and a low affinity for potassium when faced with ECF, preparing the pump for another ion transport cycle against concentration gradients.
Step-by-step explanation:
The dephosphorylated conformation of the sodium potassium pump has a high affinity for sodium (Na+) and a low affinity for potassium (K+) when exposed to Extracellular Fluid (ECF).
During the cycle of the sodium-potassium pump, once the pumped sodium ions are released into the extracellular fluid, the pump undergoes a conformational change. This change is associated with the binding of ATP and the removal of a low-energy phosphate group from the pump. It results in increased affinity for sodium ions that are abundant in the extracellular fluid and decreased affinity for potassium ions, leading to the binding of sodium ions from the extracellular fluid and a readiness of the pump for another cycle of transporting ions against their concentration gradients.