BCH-10 Nitrogen Metabolism

BCH-10 Nitrogen Metabolism - The Metabolism of Nitrogen...

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The Metabolism of Nitrogen – Much of the nitrogen in most living organisms does not come from the atmosphere directly, but through bacteria. Some by free-living nitrogen-fixing bacteria and most by a symbiotic association of bacteria fixing nitrogen in root nodules of leguminous plants (peas, beans or clovers). hey convert molecular nitrogen into ammonia They convert molecular nitrogen into ammonia which is incorporated into the amino acid glutamate a precursor of other amino acids which are the building blocks of proteins and contribute to the synthesis of other biological molecules such as: nitrogenous bases of DNA and RNA, nucleotide coenzymes like NAD and NADP, pyrole ring structures, neurotransmitters and hormones.
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Amino acids are connecting links between metabolic pathways. Excess nitrogen can be toxic and needs to be eliminated from the body as ammonia, urea or uric acid. What Constitutes Nitrogen Metabolism? – Nitrogen Fixation – the process where molecular nitrogen is converted to ammonia and then incorporated into organic compounds. Nitrates may also be incorporated in organic compounds by plants and bacteria. Nitrification – Nitrate reduction into ammonia offers another way for organisms to obtain nitrogen. Denitrification – Reactions which return nitrogen to the atmosphere.
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How is Nitrogen Incorporated Into Biologically Useful Compounds? – Bacteria fix nitrogen to ammonia in the nodules of legumes, such as beans and clover. Many free-living bacteria and some cyanobacteria also fix N 2 . Ammonia is a useful fertilizer in the spring for young plants that have less light energy to be able use nitrates and the ammonia goes to plants to use nitrates and the ammonia goes to plants rather than bacteria under those conditions. Plants and animals can’t carry out nitrogen fixation. The Nitrogenase enzyme complex found in nitrogen-fixing bacteria, catalyzes the production of ammonia from molecular nitrogen. N 2 + 8 e - + 16 ATP + 10 H + 2 NH 4 + + 16 ADP + 16 P i + H 2
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Ferredoxin is one of the proteins in the complex and there are two proteins specific to the nitrogenase enzyme: the FeS protein called dinitrogen reductase and the FeMo protein called dinitrogenase.
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About half of the ATP produced from photosynthesis in legumes is used to fix nitrogen. What Role Does Feedback Inhibition Play in
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BCH-10 Nitrogen Metabolism - The Metabolism of Nitrogen...

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