Sodium - Potassium pump Flashcards
What direction do the ions move?
Na+ out of cells and K+ into cells against steep concentrations
What does the sodium potassium generate?
Concentration gradients between cells and their environments
When can keeping a concentration gradient be important?
In the gut where sodium aids glucose absorption.
How many sodium ions are pumped out for each 2 Potassium ions absorbed?
3
What is the potential difference created essential for?
The resting potential in nerve cells.
What can be used to inhibit the the sodium-potassium pump?
Digoxin from foxglove
What happens when the sodium potassium pump is in the conformational state with a high affinity for intracellular sodium?
It exposes three binding sites to the cytosol. Three Na+ move in and bind to these sites.
Why is this protein classified as an ATPase
When 3Na+ are attached, the protein is able to hydrolyse and ATP molecule.
Where can the phosphate be found?
Bonded to part of the protein
What does this phosphorylation cause?
A conformational change to the protein
Describe the effect of this second conformation
Has a lower affinity for for Na+ ions and it can only release these ions into the extracellular fluid, thus pumping the 3Na+ ions out of the cell
What does the second conformation have a higher affinity for?
K+ ions from the extracellular fluid, two of which attach themselves to the binding sites
What happens when two K+ ions attach to the binding sites?
The phosphate is released.
What happens during the dephosphorylation?
Restores the protein to its original conformation
What does the low affinity for K+ result in?
The release of two K+ ions into the cell. The cycle repeats.
