explain active transport of Na+ and K+ in plasma membrane.?

Answer 1

There are pores across the plasma membrane.These pores are made up of proteins. These proteins hold these ions and push them in and out so that ultimately there are larger number of Na+ outside and larger number of Ka+ inside the membrane.This is against the law of diffusion which says that the substance moves from higher to lower concentration to finally attain equilibrium. This rule is overridden by these pumps, which means that it is working against the basic principle. For this purpose it has to expend energy, and this comes from the breakdown of ATP.
Why should a membrane do that is another story.
I have tried to give a simple explanation which may not be bookish or encylopedish so that you may begin to look at it afresh and find it easier to digest.

Answer 2

Sometimes substances must be pumped against a concentration gradient,such as the sodium ions and potassium ions pump.So a transport protein and energy usually adenosine triphosphate(ATP),the energy rich compound,are needed yo push the ions against the gradient.In the case of sodium and potassium ions,maintaining sodium outside potassium inside the cell is crucial to the functioning of muscles and nerves.The following mechanism illustrates an active transport mechanism.

1.Sodium ions inside the cell bind to the transport protein as a phosphate is added from an ATP,which changes the shape of the
transport protein.

2.The new transport protein structure carries and deposits the sodium to the exterior and bonds with the potassium ion,loses the phosphate group and allows for the return trip.

3.The potassium deposited inside the cell and a sodium ion and a phosphate are attached to a transport protein and the process is repeated.

Hopes this help.

Answer 3

In order to maintain the cell potential, cells must keep a low concentration of sodium ions and high levels of potassium ions within the cell (intracellular). Outside cells (extracellular), there are high concentrations of sodium and low concentrations of potassium, so diffusion occurs through ion channels in the plasma membrane. In order to keep the appropriate concentrations, the sodium-potassium pump(Na+/K+ pump or sodium-potassium pump is an enzyme located in the plasma membrane) pumps sodium out and potassium in through active transport.

The mechanism is:

* The pump, with bound ATP, binds 3 intracellular Na+ ions.
* ATP is hydrolyzed, leading to phosphorylation of the pump at a highly conserved aspartate residue and subsequent release of ADP.
* A conformational change in the pump exposes the Na+ ions to the outside. The phosphorylated form of the pump has a low affinity for sodium ions, so they are released.
* The pump binds 2 extracellular K+ ions, leading to the dephosphorylation of the pump.
* ATP binds, and the pump reorients to release potassium ions inside the cell so the pump is ready to go again

Answer 4

this kind of transport takes place in the tissues which are very active....like the nerves for example for transmission of messages.if i am not wrong then there is a low concentration of sodium ions in the cell and a high conc. of potassium inside.this conc. is maintained by an enzyme called Na-K ATPase.the enzyme binds 3 Na and throws it outside ans it binds 2 K and throws it inside,in laymans language.this is particularly seen in muscle and nerve cells to maintain osmolarity and also to create impulses.

Answer 5

Na+ and K+ ions fit into the molecular frameworks which make up the cell wall.