Sodium - Potassium pump Flashcards Preview

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Flashcards in Sodium - Potassium pump Deck (15):
1

What direction do the ions move?

Na+ out of cells and K+ into cells against steep concentrations

2

What does the sodium potassium generate?

Concentration gradients between cells and their environments

3

When can keeping a concentration gradient be important?

In the gut where sodium aids glucose absorption.

4

How many sodium ions are pumped out for each 2 Potassium ions absorbed?

3

5

What is the potential difference created essential for?

The resting potential in nerve cells.

6

What can be used to inhibit the the sodium-potassium pump?

Digoxin from foxglove

7

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.

8

Why is this protein classified as an ATPase

When 3Na+ are attached, the protein is able to hydrolyse and ATP molecule.

9

Where can the phosphate be found?

Bonded to part of the protein

10

What does this phosphorylation cause?

A conformational change to the protein

11

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

12

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

13

What happens when two K+ ions attach to the binding sites?

The phosphate is released.

14

What happens during the dephosphorylation?

Restores the protein to its original conformation

15

What does the low affinity for K+ result in?

The release of two K+ ions into the cell. The cycle repeats.