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

Transport with the help of membrane protein, Transport with the Help of Mem...

Transport with the Help of Membrane Protein Even though, the lipid bilayers do not permit the entry of polar molecules such as ions, sugars, amino acids, nucleotides and cell

Population, Population was defined by Clarke in 1954. The term populat...

Population was defined by Clarke in 1954. The term population refers to the total number of individuals of a sp. occupying a particular geographic aera at a given time. A s

Are environmental phenotypical changes, Are environmental phenotypical chan...

Are environmental phenotypical changes transmitted to the offspring? Changes caused on phenotypes by the environment are not transmitted to the offspring (unless their primary

Chemical stress, Chemical Stress Survival of cells is dependent on car...

Chemical Stress Survival of cells is dependent on carrying out of a set of chemical reactions (metabolic reactions) in a particular order. This results in a net gain in mass a

Variation of the photosynthesis effectiveness, Q. What is an example of a l...

Q. What is an example of a lab experiment that shows the variation of the photosynthesis effectiveness in relation to different photic energy frequencies to which the reaction is e

Define about the photometry - colorimetry, Define about the Photometry - co...

Define about the Photometry - colorimetry? Photometry is the measurement of the luminous intensity light or the amount of luminous light falling on a surface from such a source

Explain zymogen, Zymogen :- an  inactive form of an  enzyme; becomes active...

Zymogen :- an  inactive form of an  enzyme; becomes active prior to its action.

Cell wall, Cell wall is the structure produced by some of the cells outsid...

Cell wall is the structure produced by some of the cells outside their cell membrane; variously composed of the chitin, peptidoglycan, or cellulose.

What is the final comparative balance of these processes?, How the water ab...

How the water absorption volume and the water transpiration volume comparatively vary in plants in a day? What is the final comparative balance of these processes? Throughout t

TAKHTAJANS classification, comparison between takhtajans and natural classi...

comparison between takhtajans and natural classification

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