Biochemical reactions - nitrate assimilation, Biology

Assignment Help:

Biochemical Reactions - Nitrate Assimilation

Nitrate is the most readily available and preferred source of nitrogen for growth. Assimilatory reduction of NO-3 to NH3 is known to occur in two steps as shown below:

1939_Biochemical Reactions - Nitrate Assimilation.png

The first step is catalysed by nitrate reductase (NR) which reduces NO-3 to NO-2 at the expense of two electrons. The second step is catalysed by nitrite reductase which - converts NO-2 into NH3 at the expense of six electrons. Nitrate reductase is Mo-enzyme like dinitrogenase and nitrite reductase is Fe-protein. The physiological source of reductant for the two reductive processes could be reduced ferredoxin - Fd(red) or reduced pyridine nucleotides (NADH or NADPH) depending upon the system. It is important to point out here that NO-3 is known to undergo dissimilation in which it is reduced to N2 gas. Such a process of nitrate metabolism is called nitrate respiration or denitrification and occurs exclusively in certain bacterial forms under anaerobic condition. The enzymes of denitrification of nitrate are called dissimilatory nitrate reductases.


Related Discussions:- Biochemical reactions - nitrate assimilation

In vivo imaging in psychiatry, In vivo imaging in psychiatry To illustr...

In vivo imaging in psychiatry To illustrate the ingenious applications to which in vivo imaging can be put, consider the use of PET in the study of hallucinations by Frith and

Microorganisms, discuss the importance of protozoa to humans

discuss the importance of protozoa to humans

Define the term diffusion, Define the terms diffusion, osmosis and filtrati...

Define the terms diffusion, osmosis and filtration. Explain why each process is important for the human body.

Define determinants of food security - food utilization, Define Determinant...

Define Determinants of Food Security - Food Utilization? It is the proper biological use of food, requiring a diet providing sufficient energy and essential nutrients, potable

Fowl spirochaetosis, Fowl spirochaetosis The causal agent Borrelia anse...

Fowl spirochaetosis The causal agent Borrelia anserina is a spiral-shaped organism about 8-30 um in length but commonly 14-15 um long and 0-3 um wide. The organisms are activel

Dilute this concentration of cells to yield 300 cells, For a particular ass...

For a particular assay, you require cells at a concentration of 300 cells per ml. In your flask of cells growing you counted a sample using a hemacytometer and found that you have

Determine some beneficial effects of phytates, Determine some Beneficial ef...

Determine some Beneficial effects of phytates? Some of the health promotive aspects of phytates include: 1) Phytic acid is a known antioxidant. Colonic bacteria produce oxyg

Overturn - thermal stratification, Overturn - Thermal stratification T...

Overturn - Thermal stratification The summer or winter stratification is seasonal. Circulation of lake water occurs twice a year, in the spring and autumn (fall) seasons by a

Electron transport and oxidative phosphorylation, Many of the free energy f...

Many of the free energy free during the oxidation of glucose to CO 2 is retained in the decreasing coenzymes NADH and FADH 2 producing while glycolysis and the citric acid cycle.

Genes and chromosomes, The gene is a distinct portion of a cell's DNA. Gene...

The gene is a distinct portion of a cell's DNA. Genes are coded instructions for making all the body needs, mainly proteins. Human beings have about 25,000 genes. Researchers have

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd