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Sodium-Potassium Ion Pump quiz #1 Flashcards

Sodium-Potassium Ion Pump quiz #1
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  • What is the primary function of the sodium-potassium ion pump in maintaining cellular homeostasis?
    The sodium-potassium ion pump maintains an electrical and chemical gradient across the plasma membrane by exporting 3 sodium ions out of the cell and importing 2 potassium ions into the cell, keeping sodium concentration high outside and potassium concentration high inside the cell.
  • How does the sodium-potassium ion pump utilize ATP during its transport cycle?
    The pump hydrolyzes ATP, leading to the phosphorylation of an aspartic acid residue on the pump, which causes conformational changes necessary for transporting sodium and potassium ions across the membrane.
  • Why is the sodium-potassium ion pump classified as an antiport, and what ions are moved in which directions?
    It is classified as an antiport because it moves sodium and potassium ions in opposite directions: 3 sodium ions are exported out of the cell, while 2 potassium ions are imported into the cell.
  • Describe the sequence of events in one complete cycle of the sodium-potassium ion pump.
    First, 3 sodium ions bind to the pump from the inside of the cell. ATP is hydrolyzed, phosphorylating the pump and causing a conformational change that exports the sodium ions. Then, 2 potassium ions bind from the outside, the phosphate group is removed, causing another conformational change that imports the potassium ions into the cell, returning the pump to its original state.
  • What is the main role of the sodium-potassium ion pump in maintaining the cell's internal environment?
    It maintains an electrical and chemical gradient by exporting 3 sodium ions out of the cell and importing 2 potassium ions into the cell, keeping sodium high outside and potassium high inside.
  • How does the sodium-potassium ion pump use ATP to transport ions across the membrane?
    The pump hydrolyzes ATP, which phosphorylates an aspartic acid residue on the pump, causing conformational changes needed for ion transport.
  • Why is the sodium-potassium ion pump considered an antiport, and which ions move in which directions?
    It is an antiport because it moves ions in opposite directions: 3 sodium ions are exported out of the cell, while 2 potassium ions are imported into the cell.
  • What are the steps in one complete cycle of the sodium-potassium ion pump?
    Three sodium ions bind from inside, ATP is hydrolyzed and the pump is phosphorylated, sodium is exported, two potassium ions bind from outside, the phosphate is removed, and potassium is imported, returning the pump to its original state.
  • What is the significance of the sodium-potassium ion pump being a P-type ATPase?
    As a P-type ATPase, the pump is phosphorylated during its cycle, which is essential for the conformational changes that drive ion transport.
  • How does the sodium-potassium ion pump contribute to the electrical gradient across the plasma membrane?
    By exporting more positive charges (3 Na+) than it imports (2 K+), the pump helps keep the inside of the cell more negative relative to the outside.