Biology cluster

Cluster will start on 20-8-11.Teachers requested to bring TB&HB

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International Year 2010 -11

2010s

• 2010 - International Year of Communications[citation needed], International Year for the Reapprochement of Cultures
• 2010 - International Year of Biodiversity
• 2010 - International Year of Youth
• 2011 - International Year of Forests
• 2011 - International Year of Chemistry, recognized by UNESCO
• 2011 - International Year for People of African descent
• 2011 - World Veterinary Year 2011
• 2012 - International Year of Cooperatives

Na+/K+ (Sodium/Potassium) Pump

Na+/K+ (Sodium/Potassium) Pump

The Na+/K+ pump is found in the membranes of many types of cells. In particular, it plays a very important role in nerve cell membranes. Notice that 3 positive ions (Na+) are pumped out of the cell (towards ECF) for every 2 positive ions (K+) pumped into the cell (towards ICF). This means that there is more positive charges leaving the cell than entering it. As a result, positive charge builds up outside the cell compared to inside the cell. The difference in charge between the outside and inside of the cell allows nerve cells to generate electrical impulses which lead to nerve impulses.

The Na+/K+ pump illustrates "active transport" since it moves Na+ and K+ against their concentration gradients. That is because there is already a high concentration of Na+ outside the cell and a high concentration of K+ inside the cell. In order to move the ions (Na+ and K+) againts their gradients, energy is required. This energy is supplied by ATP (adenosine triphosphate). An ATP molecule floating inside the cell, binds to the pump transferring some energy to it. As the energy is used, the ATP falls off and having lost its energy it is converted into ADP (adenosine diphosphate).

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BIOLOGY TIRUR WELCOME