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13 Cards in this Set
- Front
- Back
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Aerobic Respiratory Chain |
*See chart Remember: 10 H+ pumped out for every 2e- that enter complex 1 BUT! ONLY 6 H+ pumped out for every 2e- that enter complex 2 |
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Oxidative phosphoylation |
Proton gradient generated by ETC is used to power ATP synthesis |
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What does respiration mean in the molecular sense? |
passing e- down an ETC & reducing and exogenous e- acceptor Eukaryotes: e- acceptor= oxygen Bacteria can use alternative e- acceptors |
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Assimilative vs. dissimilative reduction |
Assimilative reduction: compounds reduced for building cellular macromolecules. Only reduces amount needed Dissimilative reduction: compounds reduced for E conservation. Large amounts reduced. Cell excretes reduced products as waste |
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What are 3 anaerobic respiration systems? |
1. Methanogenesis 2. Ferric iron reduction 3. Nitrate reduction & denitrification |
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What is denitrification? |
Conversion of nitrite into gaseous compounds that're lost from soil & water |
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What is nitrate reduction? |
Nitrate --> nitrite *process performed by facultative aerobes. They can use O2 or NO3- as an e- acceptor but prefer oxygen Oxygen must be absent & nitrate must be present |
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What is the paradox of denitrification? |
It should be almost as energy-yielding as aerobic respiration b/c NO3/ .5N2 couple is located very close to O2/ H2O couple on e- tower BUT it's not!!! |
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Why is energy yield from denitrification not as great? |
1. energy from nitrite reductase & nitrous oxide reductatse can't be stores as PMF 2. ETC isn't linear so proton pumping opportunites for a pair of e- is limited 3. nitric oxide reductatse pulls proton from the periplasmic space so it doesnt contribute to PMF |
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What are 3 mechs to access mineralized Fe3+? |
1. Produce & excrete chelators for Fe3+ to make it soluble 2. Use e- shuttling compounds that're reduced by the cell but then diffuse away and reduce Fe3+ @ a distance 3. Touch the mineral directly |
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How do you touch the mineral directly during ferric iron reduction? |
1. Type 4 pilie are required. Use nanowires w/ attached cytochromes 2. pili not required. different type of nanowire that has outer membrane extensions. Have cytochromes & e- are thought to hop directly from 1 to another on the membrane surface |
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What is methanogenesis? |
performed by Archaea who are strict anaerobes Carbon in CO2 is terminal e- acceptor and fully reduced to methane occurs when lots of H2 and CO2 substrate are made by fermenters |
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Why is methanogenesis interesting? |
requires: 1. unique one carbon carriers 2. unique e- donating co-factors 3. sodium ions are pumped across IM & generate a sodium proton force |
