Give the biochemical events occurring in the root nodule of a pulse plant. What is the end product? What is its fate ?

Explanation

Formation of root nodule in pulse plant is the result of infection of roots by Rhizobium.
The following figure shows the process of nodule formation

The chemical reaction is as follows
`N_(2)+8e^(-) +8H^(+)+16 " ATP" rarr2NH_(3)+H_(2)+16 " ADP"+P_(1)i`
The reaction takes place in presence of enzyme nitrogenase which acts in anaerobic conditions created by leghaemoglobin.
Fate of Ammonia
There are two ways by which ammonia is further used
(a) Reductive Amination
`alpha`-ketoglutaric acid `+ NH_(4)^(+)+underset("Dehydrogenase")overset("Glutamate")rarr "glutamate"+H_(2)O + "NADP"`
Ammonia reacts with `alpha`-ketoglutaric acid to from glutamate.
(b) Transamination
`R_(1)-underset(NH_(3)^(+))underset(|) overset(H)overset(|)C-CO O^(-)+R_(2)-underset(O)underset(||)C-COO^(-)hArrR_(1)-underset(O)underset(||)C-COO^(-)+R_(2)-underset(NH_(3)^(+))underset(|) overset(H)overset(|)C-CO O^(-)`
In this process, transfer of `NH_(2)` group take place from one amino acid to other amino acid, enzyme transaminase catalyses this reaction.