sodium -potassium pump

1. SODIUM – POTASSIUM PUMP
Dr Shweta Gaur
Assistant Professor
Chemistry

2. MEMBRANES
• Plasma membrane is an envelope surrounding the cell
• Acts as a protective barrier from external environment
• Provides connecting system between cell and its
environment
• Membrane forms a barrier for the free passage of
compounds across it

3. MECHANISM OF TRANSPORT THROUGH THE MEMBRANE
Passive transport Facilitated transport Active transport
Moves through the
membrane due to
concentration gradient ie
(higher to lower)
Solute moves along the
concentration gradient
Occurs against the
concentration gradient
No energy required No energy required The energy required is
obtained by breakdown of
ATP
Passage of water and gases
occur
Occurs through the carrier
proteins
Na+ and K+ are transported
through active transport
Dr Shweta Gaur

4. SODIUM - POTASSIUM PUMP
• Example of Active Transport
• Actively removes Na+ from the cell and
accumulate K+ into the cell from the
surroundings.
• This pump is present in all parts of the
body.
• Na+ & K+ gradients across the
membranes are needed for the
transmission of nerve impulse.
Dr Shweta Gaur

5. Mechanism of action of Na+ - K+ pump
• Na ions from the cell get attached to the receptor sites of Na+ on the inner
surface of the membrane.
• K ions outside the cell bind to the receptor sites of K+ located on the outer surface
of the membrane
• The binding of Na+ & K+ to the membrane immediately activates the ATPase.
ATPase causes the break down of ATP to ADP with the release of one high energy
phosphate.
Dr Shweta Gaur

6. Mechanism of action of Na+ - K+ pump
• Now the energy liberated causes some sort of conformational change in the
membrane.
• Because of this, the outer surface of the membrane with K+ , now faces the inner
side of the cell.
• And the inner surface of the membrane with Na+ faces the outer side of the cell.
• Now release of the ions takes place so that the Na+ are released out side the cell
and the K+ are released inside the cell.
Dr Shweta Gaur

7. Mechanism of action of Na+ - K+ pump
• Na+ -K+ Pump moves 3 Na+ outside the cell and 2 K+ inside the cell.
• When the pump works once, there is a net loss of one positive charged ion from
the cell.
• The continuous activity of these Na+ -K+ Pump causes reduction in the number of
positive charged ions inside the cell leading to the development of negative
potential inside the cell.
Dr Shweta Gaur

8. • Maintain the right concentration of ions inside the cell: If the concentration is high
inside the cell then water flows inside the cell through osmosis. As a result cell
and lyse
• Transport: Export of sodium from the cell provides the driving force for several
secondary active transporters membrane transport proteins which import glucose,
amino acids and other nutrients into the cell by the use of sodium gradient
Dr Shweta Gaur
Role of Sodium – Potassium pump

9. THANKS