Question

Where is nitrogen fixing bacteria found?

Answer 1

Hint: Nitrogen fixation is the process of converting atmospheric nitrogen into inorganic nitrogen by the aid of bacteria and other living organisms. Nitrogen fixing bacteria can be found in the root nodules of the plants and some of them are free-living. These bacteria are found in soil and aquatic regions.

Complete answer:
Nitrogen fixation is an important phenomenon in nitrogen cycle as well as in plant growth. Nitrogen fixation mechanism is abundantly found in leguminous plants. nitrogen fixing bacteria are of two
Free-living or non-symbiotic bacteria: These bacteria are not attached to any parts of the plants and are free-living. The following are some of the examples of free-living nitrogen fixing bacteria: Clostridium, Nostoc, Anabaena, and Azotobacter.
Symbiotic or mutualistic bacteria: These bacteria penetrate the root of the plants and form root nodules. These bacteria use plants as their hosts. This is where atmospheric nitrogen is converted into ammonia. Examples of symbiotic bacteria are Rhizobium and Azospirillum.

Additional information: Nitrogen fixing bacteria converts nitrogen into ammonia. Nitrifying bacteria convert ammonia into nitrites or nitrates, e.g., Nitrosomonas, Nitrobacter. Denitrifying bacteria convert these nitrites or nitrates back to nitrogen, e.g., Pseudomonas.

Note:
Atmospheric nitrogen in gaseous form is not suitable for plant intake. That is why nitrogen fixing bacteria helps fix it by converting nitrogen into ammonia for the intake by plants. Nitrogen fixation is essential in plants because they play an important role in synthesizing all compounds made up of nitrogen such as DNA, RNA or proteins.