Question

Why does nitrogen assimilation in plants cost energy?

Answer 1

Nitrogen assimilation in plants cost energy because of the following reasons- Nitrogen assimilation is the process by which inorganic nitrogen present in the environment is converted into organic nitrogen components . Plants cannot absorb nitrogen directly from the environment. Plants and even certain bacteria do not have capability to fix nitrogen but it is required for normal growth and development. So as we know that plants cannot take nitrogen directly and can take it in forms of nitrate NO3- and ammonia NH4+. So for carrying these type of ions there are several transporters which are present in the plants like ammonium ions are carried by ammonia transporters while nitrate by transporters that use proton gradient to derive energy for transport.Now this proton gradient activity requires reducing electrons and ATP produced from the photosynthetic activity of plant using light energy as the source.This use of ATP and reducing electrons to carry these ions against the potential gradient inside the plants requires alot more energy and it requires energy.Nitrate when once reaches inside the plants is further degraded into nitrite by using certain enzymes which also use NADH or NADPH. So nitrogen assimilation in plants cost energy.

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