Nitrogen fixers

Nitrogen is important for all organisms since it is one of the components of proteins and nucleic acids (DNA).
Most living species cannot directly absorb nitrogen from the atmosphere, of which this gas is the largest component (78%). Only some bacteria can transform gaseous nitrogen into compounds that can be absorbed by the other living beings (especially vegetal organisms) through a series of metabolic reactions that are jointly called “nitrogen fixation”. Nitrogen, included in more complex molecules, such as ammonia and nitrates, is part of the food chain. The most important nitrogen-fixing organisms are cyanobacteria, also known as blue algae, which live in water. On the mainland, this function is mainly served by the Azotobacter that live son earth and by the Rhizobium that lives in symbiosis in the roots of the plants of the genus Leguminosae (bean, lentil and clover).

 
Download "Bacteria knowledge" pdf file
Download the junior version pdf file
 

Special reports

  • 3 November 2014

    Conan the bacterium

    Have you ever leafed through the pages of a book of Guinness World Records? You can find records of all…

  • 5 February 2010

    Extreme bacteria

    Researchers from the Cnr with Bruno D’Argento and...

  • 4 March 2010

    Biotechnological cleaners

    In today’s society, more than 80% of human activities are...

From the Multimedia section

Facts