Does bacteria fix nitrogen?
Some bacteria that are helpful but the virus bacterias never do. So it really depends!
Because nitrifying bacteria can fix atmospheric nitrogen in to chemical compounds. This nitrogen fixed by bacteria is utilized by plants in making proteins. Again several microbes including bacteria decompose organic matter in to inorganic compounds. Thus nitrogen cycle is maintained by the activity of bacteria, hence these are critical to nitrogen cycle.
Although the air is made up of about 70% nitrogen, plants cannot use nitrogen in this N2 form. Nitrogen fixing bacteria change nitrogen into the form of soluble nitrates so that plants can use it. Other bacteria, known as de-nitrifying bacteria, change nitrates back into N2, which completes the nitrogen cycle They fix nitrogen into forms usable by plants.
Some Bacteria fix nitrogen from the air and give it to plants, others degrade complex organic compound into inorganic elements which are taken by the plants; in return plants synthesize organic compounds used by bacteria for energy. Bacteria associated with plants to fix nitrogen and benefited by the plants for space and energy are called symbiotic bacteria.
Because leguminous plants are those plants which have nitrogen fixing bacteria in their roots in the modules of nitrogen. thus to fix the nitrogen to the soil or in crops is the work of those bacteria namely rhizobium and azotobacter thus without these plants we wont have these bacterias and alos the nitrogen
What do nitrogen fixing bacteria use to split molecules of nitrogen gas and combine the nitrogen atoms with hydrogen?
The bacteria fix nitrogen by converting it to ammonia and nitrates which the plant can absorb and use to build its nitrogen containing molecules such as amino and nucleic acids. In return it offers some of its own sugars to the bacteria to cover their needs. It's a trade off between biologically usable nitrogen and sugar