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

Define influence of polyphenols on carbohydrates, Define influence of polyp...

Define influence of polyphenols on Carbohydrates? Binding of proteins may indirectly affect carbohydrate absorption. Inhibition of amylolytic enzymes and subsequent reduction o

Explain which provides barrier to the movement of molecules, In a plasma me...

In a plasma membrane, which of the below provides a general barrier to the movement of molecules? a) Lipids b) Proteins c) Carbohydrates d) all of these Answer: a

How walking benefits for the health, Walking In the process of walking ...

Walking In the process of walking the motion of the two legs is coordinated so that one foot or the other is always in contact with ground. Walking is the best form of exercise

Coelentrates, classification of coelenterats?

classification of coelenterats?

In which bones can bone marrow chiefly be found, In which bones can bone ma...

In which bones can bone marrow chiefly be found? Is the bone marrow made of osseous tissue? Bone marrow can mostly be found in the internal cavities of flat bones, as the verte

Define observation or inference for fehling's test, Define Observation or I...

Define Observation or Inference for fehling's test? An insoluble reddish brown precipitate of cuprous oxide will be obtained. The reddish brown precipitate indicates the presen

A plant growing on a mountainside, What two abiotic factors might affect (a...

What two abiotic factors might affect (a) an animal living at the bottom of the sea, (b) a plant growing on a mountainside?   (a) The abiotic factors which might

Explain intensity of heart sound, Explain Intensity of heart sound? Int...

Explain Intensity of heart sound? Intensity of S 1, particularly M 1 depends on the position of the bellies of mitral leafets when the LV begins to contract since S 1 is loudes

Some important zoonoses-rabies , Some important zoonoses Zoonoses are ...

Some important zoonoses Zoonoses are a heterogeneous group of diseases with a variety of causative agents. On the basis of causative agents, they are grouped into bacterial, p

Implant exposure - implant surgery, Describe Implant exposure ? Sound su...

Describe Implant exposure ? Sound surgical principles to minimize the surgical exposure based on the access required should be employed. A series of surgical approaches to achie

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