Sodium-Potassium Pump Mechanism

Sodium-Potassium Pump

• The sodium-potassium pump is a protein that moves sodium and potassium ions across the cell membrane.
• It is an active transporter, meaning it requires energy to function, provided by the breakdown of ATP.
• Mechanism:
  • The pump binds three sodium ions inside the cell.
  • ATP is hydrolyzed, releasing energy that changes the shape of the protein and causes it to face outwards.
  • Sodium ions are released outside.
  • Two potassium ions bind to the protein on the outside.
  • The protein changes shape again, facing inwards, and releases potassium ions inside the cell.
• Key characteristics:
  • Moves ions against their concentration gradient: sodium is moved from a low concentration inside to a high concentration outside, while potassium moves from a high concentration outside to a low concentration inside.
  • Requires ATP hydrolysis for energy.
  • Creates concentration and electrical gradients across the cell membrane, which contribute to nerve impulse transmission and muscle contractions.
• Important for cell functioning:
  • Maintains resting membrane potential, which is crucial for nerve impulse transmission and muscle contractions.
• ** Concentrations:**
  • Inside the cell: Sodium ~10 meq/L, Potassium ~142 meq/L
  • Outside the cell: Sodium ~142 meq/L, potassium ~10 meq/L

This quiz explores the mechanism of the sodium-potassium pump, a vital active transporter in cellular biology. It details how the pump moves sodium and potassium ions across the cell membrane using energy from ATP. Test your understanding of its key characteristics and functions.