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50 Cards in this Set
- Front
- Back
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What does Nitrogen assimilaton consist of? |
NO3 to NO2 to NH3 |
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Describe the first step of nitrogen assimilation? |
Nitrite reductaste: NO3 to NO2
The reductase uses NADH to reduce NO3 alogn with the MO cofactor |
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Describe the second step of nitrogen assimilation? |
Nitrate reductase: NO2 to NH3 Use ferrodoxin as an electron supply to reduce the Fe-S and transfer that to Siroheme |
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What are the difference Nitrogen assimilation and Nitrogen fixation? |
• Both are electron-transfer processes • Both use Mo cofactor– Nitrate reductase has an Mo cofactor– The nitrogenase complex has an Fe-Mo cofactor • Both processes involve electron transferthrough groups such as Fe-S complexes,cytochromes, SH groups, NADH, NADPH, etc. • Nitrate Reductase, Nitrite Redcutase geneexpression is induced by NO3 |
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What is the Ammox reaction? |
Anaerobic Ammonia oxidation Bacteria able to oxidize ammonia and nitrate acid into nitrogen without going through denitrification |
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WHat is unusual about the phylum Planctomycetes? |
Anamox bacterias: Able to synthesize and use hydrazine(rocket fuel) , toxi, reactive, nonpolar and diffuse across membrane Phospholipid mades of ladderanes -fatty acid chain contains cyclobutane rings that stack tightly, slow hte diffusion of N2h2 |
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What does the reaction of Anammox look like? |
Ammonium and NH2Oh can enter the hydrazine hyrolase and make Hydrazine which reacts with a oxidizing agent to reduce nitrite into NH2 and leads to production of nitrogen gas |
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what does ladderane membranes do |
Ladderanes are just phospholipisd htat prevents the diffusion of hydrazine which is lethal. Bacterias that are known to have ammox reactions have huge anammosomes to prevent the diffusion(membrane-bound) |
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What does amino acid have anything to do with the nitrogen cyle |
Amino acids and other reduced nitrogen carbon compounds can be degraded into ammonia or reverse where ammonia is transformd into reduced nitrogen-carbon compound
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What is the source of nitrogen in regards to Amino Acid biosynthesis? |
Glu or Gln Which comes from the intermediates of glycolysis, citric acid cycle and pentose phosphate pathway. Bacteria, Plants, Fungi synthesize all 20 while mammals lack some pathways to create the essential amino acids |
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What happens to Ammonia in a biological organism? |
Glutamine is made from Glu(glutamic acid) by Glutamine Synthetase. |
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What is the mechanism to making Glutamine from Glutamic acid? |
Glutaminic Acid reacts with ATP to add a phosphate onto glu which can act as a good leaving group. This allow Ammonia to displace the phosphate to make Glutamine. |
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How is Nitrogen incorporated onto Oxoglutarate? |
Ammonia is carried onto glutamate to form glutamine through the synthetase. However, theres is a glutamate synthase that adds a nitrogen group onto 2oxoglutarate to form glutamate Glutamate can be used to make amino acids, nucleic acids, and etc or be used in the carbon cycle |
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How do you regulate glutamine Synthetase by allosteric inhibitor? |
The endpoints of Glutamine metabolism provide allosteric feedback inhibition. Build up of Ala, Gly, Trp, carbamoyl phosphate, AMP , CTP inhibits it, so it doesn't wanna keep making too much glutamine Effects are additive |
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What is the pathway of the allosteric inhibitor? |
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What is Glutamine synhtetase inhibit by? |
Adenylylation -attachment of AMP to Tyr-397 - help with inhibition By doing that yit increases the enzyme sensitivity to inhibitors Adenylation by adenyltransferase -regulated by regb protein Pll |
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What is Pll regulate by? |
Uridylylation Pll -ump stimulates deanylylation of Glutamine synthetase ( increase synthetase activity) - also upregulates transcription of glutamnie synthetase genes |
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What increase acitvity of Glutamine synthetase? |
When glutamine levels are low , a-ketoglutarate and atp are high The enzyme becomes more activate which allows to convert more ammonia to glutamine |
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Whati sthe effect of high gltamnie? |
GLn synthease is reduced because you dont wat to convert ammonia to GLN becuase u already have so much
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DESCRIBE THE COVALENT MODIFICATION of GLN synthetase |
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What are the three type of reactions that allow biosynthesis of Amino Acid Nucleotide? |
1. Transamination and rearrange using Pyridoxal phosphate -catalyze by adminotransferase - use aldehyde group that forms schifff base with Lys of the catalyst 2. Transfer of 1-C groups using Tetrahydrofolate or S-adensoylmethionine(adoMe) -both act as acarbon donor 3. transfer of amino group deried by glutamine amidotransferase - glutamate synthase , GOGAt |
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2.What is the structure of Glutamine Amidotransferase? |
Two Domains: - One binds to Gln - Other is amino group acceptor and bind to substrate Cys acts as a nucleophile to cleave amide bonds of Glutamine -creates intermediate Second substrate binds to accept amino group from enzyme |
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What is mechanism of Glutamine Admidotransferase? |
Cys acts as a nucleophile to cleave amide bonds of Glutamine -creates intermediateSecond substrate binds to accept amino group from enzyme Propose: Is that it binds to the carbonyl of glutamine and the ammonia is release into the channel where it can react with the substrate |
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What are the seven precursors that all amino acids are derived from? |
TCA cycle -a-ketoglutarate, oxaloacetate Glycolysis -pyruvate, 3PG, PEP, Erythrose Pentose phosphate -ribose 5 phosphae |
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What is a-ketoglutarate a precursor for? |
Glutamate Then that can be converted to Glutamine, Proline,Arginine |
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How is Proline and Ariginine derived from Glutamate? |
Proline is merely a cyclized reduced version of Glutamate. - Atp reacts with the gamma carboxyl group to form acyl phosphate -Reduction of acylphosphate to a semialdehyde that clyclize - to form Proline -Reduce either NADH or NADPH PATHWAY BY ANIMAL AND BACTERIA |
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How do you make Arginine? |
Glutamate gets acetylated by synthase to form N-acetylglutamine. ATP reacts with NAG by adding a phosphate onto the gamma where it gets redued to a aldehyde. An aminotransferaseb transfers a nitrogen group from the glutamate in return gets a cooh It goes through the urea cycle to form Arginine |
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What is the purpose of orthinine? |
It coems from glutamine , but it is used in the urea cycle to get arginine Ornithine comes from GLu to arginine in animals |
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How can pronline be synthesize from arginine? |
Arginase converts Arg to Ornithine Ornithine aminotranfserease converts it to a semialdehyde that cyclized to Proline |
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How does Mammals convert Ornithine to cyclizd/ |
Ornithine comes from Args which does aminotransferase with A-ketogltarate to gain a semialdehyde. |
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What does the precursor 3-Phosphoglycerate produce? |
Serine which can be used to produce Glycine and Cystein
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What produces 3PG? |
Product of Glycolysis Same pathway in all organism. Requries Glutamate as a source of nitrogen group |
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What is the mechanism of Serine form 3PG? |
Oxidation of 3PG Transamination with Glutamine Dephosphorlyation to yield serine |
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How is glycine a derivative of Serine?
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Carbon remove using tetrahydrofolate(h4) to accept the C atom and PLP
Reaction uses serine hydroxymethyltransferase Liver, gly is made by another pathway. |
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How is cysteine derived from Serine? |
In bacteria and plants, sulfate is the source of S. In Animals, Methione is the source of S. |
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What is the biosynthesis pathway of Cys from Ser in Plants and Bacteria? |
1. Atp binds with sulfate 2. The Adenosine 5'-phosphosulfate binsd with another atp to form PAPs(two phosphate) 3. Paps get reduced by NADPH to get sulfite which gets reduced into Sulfide(s^2) 4. The sulfide is used with a acetyleted Serine to form Cysteine |
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What is the biosynthesis pathway of Cys from Homocysteine and Ser? |
Homocystein and Serine reacts with each other with PLP to form Cystathione It then gets split up by hydrolysis to remove ammonia group from the homocystein part to create cystein after the split |
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What is Oxaloacetate a precursor for? |
Aspartate -> Asparaginine, Methionine, Lysine and Threonine |
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What is the pyruvate a precursor for? |
Alaniine, Valine, Leucine, Isoleucine |
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What can be threonine converted to ? |
Isoleucine(Ile) or pyruvate-> ille |
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What does aparaginase do? |
It is a bacteria derived enzyme that is used as a chemotherapy agent
Acute Lymphoblastic lekeumeia depends on serum Asn Therefore Asparginase can remove Asn along with a human Asn Synthease inhibitor |
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What is PEP and erthyrose 4 phosphate a precursor for? |
Phenyalanine->tyrosine, tyrosine tryptophan |
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What doe the reaction of PEP and erthyrose produce in term of intermediate? |
Chorismate through rings being synthesize and closed then oxidized to create double bonds |
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How are tyrosine and Phenylaline produce? |
Basicalyl the chorismate gets mutased, where it can either undergo reduction or release of carbon dioxide The reduction leads to tyrosine through a transamination The release of carbon dioxide leads to phenylaline through transmination |
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What is Ribose 5 phosphate a precursor for? |
Histidine |
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What is the mechanism of the formation of Histidine? |
Utilized ATP prunie ring with PRPP from PPP and GLn for N |
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How is amino acid synthesi sregulated? |
1. Enzyme regulation 2. Feedback inhibition can be coupled with allosteric regulationW |
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What is an example of allosteri regulation? |
isoleune synthesi sfrom THR -Threonine dehydratase is inhbit by Ile |
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What is the allosteric regulation of Ile synthesis from Thr? |
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What do isozymes play in the regulation of amino acid synthesis? |
There are multiple variation of the enzyme that can catalyzet he reaction however each isozyme can be allsoteric differently by different amino acids to prevent the absolute shortage of amino acid |
