Term
plants have a symbiotice relationship with nitrogen fixing bacteria to convert molcular nitrogen (N2) into___. this is the 1st stable product however it is protonated and then converted into ___. this consumes 16 ATPs per nitrogen |
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Definition
Ammonia(NH3)
Ammonium (NH4) |
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Term
Assimilation of sulfur (SO42-) into the amino acid ___ via 2 pathways found in plants consumes __ amout of ATPS. |
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Definition
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Term
The Harbor Bosch process involves what? |
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Definition
| it involves elveating the temper and and pressure and ususally the presence of a metal catalyst (usualy iron) so that nitrogen can combind with hydrogen to form ammonia which can then be oxidized to make nitrates and nitrites. |
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Term
why is too much ammonium dangerous? |
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Definition
| it dissipates transmembrane proton gradients that are required for photosynthtic and respiratory electron transport. |
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Term
Natural prcess which fix nitrogen
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Definition
Lightning (converts water vapor and oxygen into hydroxy free radicals that attack nitrogen to form nitric acid.
photochemical reactions (reaction between gaseous nitric oxide and ozone)
biological nitrogen fixation (bacteria such as blue green algae fix N2 into ammonium) |
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Term
what is the first step in nitrate assimilation? |
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Definition
| using the enzyme nitrate reductase to reduce nitrate to nitrite in the cytosol. |
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Term
Plant roots absorb __from the soil via several low and high affinity __? |
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Definition
Nitrate
nitrate proton cotransporters |
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Term
Nitrate reductatse is composed of what? |
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Definition
molybdyeum--heme--FAD---NADH
The FAD accepts 2 electron from the nadh which are sent down the chain. |
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Term
nitrate reductase is influenced by __, __, and __ and is controlled at what levels? |
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Definition
nitrate, light, carbohydrates,
trancriptionally translationally and posttranslational |
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Term
Nitrite reductase converts nitrite into __ |
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Definition
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Term
Explain the process of nitrite being reduced to ammonium
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Definition
| The nitite produced by the nitrate reductase in the cytosol is very toxic to plants therefore they immediatly send it to the chloroplast and root plastids. these organells have nitrite reductase to turn nitrite to ammonium. They both contain ferrodoxine that comes from photsynthetic reaction, ferro is reduc and oxidized. the nitrite reductase contains 2 pros groups an Iron-sulfure (Fe4S4) complex and a heme that both bind nitrite and converts to ammonium. **rem H+---->NH4, nitrite (NH2-) ---->nitric oxide |
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Term
elevated levels of __ and ___ will induced transcription of nitrite reductase,
however if there is too much of the end product of ___ and ___ transcription will be repressed (act as feedback) |
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Definition
NO3 (nitrate) and light
asparganine and glutamine |
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Term
plants avoid ammonium toxcitiy by rapidly converting the ammonium generated from nitrate assimiliation or photorespiration into ____ |
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Definition
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Term
The primary pathway of ammonium assimilation involves
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Definition
glutamine synthetase and glutamate synthase |
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