Ncert Exercises & Solutions

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

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} + 8 e^{-} + {BH}^{+} + 16 ATP ⟶ 2 {NH}_{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

α - k e t o g l u t a r i c acid + {NH}_{4}^{+} + NADPH \to_{D e h y d r o g e n a s e}^{G l u t a m a t e} glutamate + H_{2} O + NADP

Ammonia reacts with

α

-ketoglutaric acid to form glutamate.

(b) Transamination

In this process. transfer of NH₂ group take place from one amino acid to other amino acid; enzyme transaminase Catalyses this reaction.