Question

what is biological fixation?how is it different from nitrification?give an example of organism involved in each of these? class 9

Answer 1

Nitrogen gas forms 48% of air . It cannot be used as such by plant nd animal . it must be converted into biological acceptable forms . A number of free living bacteria ( Azobacter nd Clostridium ) Symbiotic bacteria Rhizobium nd blue green algae take up free atmospheric nitrogen nd convert it into ammonia that combines with organic acid to form amino acid . the latter r used to form protein . this process called biological fixation .

Nitrogen fixation is the process in which the atmospheric nitrogen is fixed by certain bacteria into ammonia.Nitrification is the process in the ammonia is oxidized into nitrite which is further oxidized nitrates.Both nitrogen fixation and nitrification are important parts of nitrogen cycle.


Organism involved in nitrogen fixation is :-

1) Rhizobium bacteria ( in root nodules of leguminous plants ).

2 ) Azotobacter in bacteria.

3) Blue green algae .


Organism involved in nitrification:-

1) Nitrosomonas bacteria .

2) Nitrobacter bacteria .

Answer 2

Biological nitrogen fixation (BNF) is the term used for a process in which nitrogen gas (N2) from the atmosphere is incorporated into the tissue of certain plants. Only a select group of plants is able to obtain N this way, with the help of soil microorganisms.
Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates - carried out in soil by the action of nitrifying bacteria on decaying organic matter.