Question

Why Cyanobacteria uses 'light and dark cycle' to prevent oxygen inhibition on nitrogen fixation?

please explain it in detail using the below reaction equation.

N2+8H+8e+16ATP-> 2NH3+H2+16ATP

Answer 1

Answer. Under the light-dark rule, the most heterocystic strain mentioned so far ideally fixes the nitrogen in the sun. Natural blooms, often dominated by heterocystic cyanobacteria, demonstrate higher production of nitrogenase in the light than in the dark.Low production of nitrogenase in the dark has been due to the failure of metabolism to generate reductive substances adequately under these conditions. In many ways, this modification is similar to the ADP-ribosylation of the nitrogenase-Fe-protein found in Rhodospirillaceae after transition from light to darkness or after addition of ammonia.Heterocysts have a thick, multilayer wall that prevents the entry of oxygen, a high rate of respiration that uses defused oxygen, and a lack of photosystem II so that there is no photosynthetic evolution of oxygen.

Answer.

○Nitrogenases are enzymes produced by certain bacteria, such as cyanobacteria (blue-green bacteria), which are responsible for reducing nitrogen (N2) to ammonia (NH3). Nitrogenases are the only family of enzymes capable of catalyzing this reaction, which is a crucial step in the process of nitrogen fixation Nitrogen fixation is necessary for all life forms, with nitrogen being important for the biosynthesis of molecules (nucleotides, amino acids) that produce plants, animals and other organisms. They are encoded by the genes or homologs of the Nif. We are related to reductase protochlorophyllide.

Ammonia (NH3), nitrogen gas (N2) reacts with hydrogen molecules (H2), usually in the presence of an iron catalyst. The process requires high temperatures and pressures, but is thermodynamically optimal as little energy is lost on side reactions. Center: Nitrogenase enzymes catalyze the reactions of six-electron (e−) nitrogen and six-proton (H+) ammonia under ambient conditions.
NeverthelessNevertheless, two additional electrons and protons form one H2 molecule. The conversion of ATP (biological energy currency) to ADP causes the reaction. This reaction has a high chemical over-potential. It absorbs a lot more energy than is required for an actual ammonia reaction.Bottom: In the new reaction proposed by Ashida and colleagues, a mixture of water and samarium diiodide (SmI2) is converted to ammonia using nitrogen in ambient conditions and in the presence of a molybdenum catalyst. SmI2 weakens the O−H bond of the water and produces hydrogen atoms, which then react with atmospheric nitrogen.