question_answer 48)

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

Answer:

                  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

	(a) Rhizobium divide near the root hair
	(b) Successful infection of  the root hair causes it to curl
	(c) Infected thread carries the bacteria to enter the cortex. Bacteria cause cortical and pericycle cells to divide, lead to nodule formation.
	(d) Mature nodule with vascular tissues  continuous with those of  the roots.

The chemical reaction is as follows 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 ketoglutaric acid  glutamate Ammonia reacts with a-ketoglutaric acid to form glutamate. (b) Transamination In this process, transfer of group take place from one amino acid to other amino acid. Enzyme transaminase catalyses this action.