Answer: The options are missing from the question.
A) Na+ is bound
B) ADP is bound
C) The pump is phosphorylated
D) The pump changes conformation
The correct answer to the question is option C
THE PUMP IS PHOSPHORYLATED
Explanation: Sodium potassium pump (Na+ K+ pump) is a mechanism that uses active transport to move sodium Na+ and potassium K+ in and out of cellular compartments (intracellular and extracellular) inorder to maintain a gradient. It is responsible for maintaning a high extracellular sodium ion concentration and a high intracellular potassium ion concentration.
Once the sodium-potassium pump hydrolyses ATP,the pump will become phosphorylated (transmission of signal throughout the cell) lowing the affinity of the pump to sodium,this causes 3 sodium ions to move out of the intracellular compartment into the the extracellular compartment. The pump further brings two potassium ions together causing a dephosphorylation(inhibition of signal transmission throughout the cell) and then moves the 2 potassium ions out of the cell. This mechanism continues till there is a higher extracellular sodium concentration and a high intracellular potassium concentration therefore achieving the desired gradient(optimum)
