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25 Cards in this Set
- Front
- Back
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what drives substrate level phos?
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high energy intermediate (between two reactions)
ex) alpha keto glut to succinyl CoA succingly coa to succinate(makes GTP) |
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P:O ratio
high vs low |
atp formed: oxygens used
nadh is about 3 succinate is about 2 |
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chemiosmotic hypothesis
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proton grad is primary means of energy transduction
mitchel 1961 |
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describe ATP synthase subunits
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a reverse proton pump
Fo - A B C - charged aa, wants proton in acidic (intermem space) doesnt want it in basic (matrix) causes motor to turn and protons to pump down [grad] F1 - alpha, beta (catalytic site, ATP SYN) gamma (connects to Fo) delta, epsilon |
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describe l t and o states for beta of F1
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l - attracts ADP and Pi
t - active, where ATP form is o - open, release (little affinity for)atp |
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is inner mem permeable or non pemeable
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very impermeable so need translocases (uaually antiport)
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two types of transport systems
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electrogenic - membrane potential ie Ca++ uniport, ATP leaves mito via electrogenic antiport with ADP
ligand - conformational change |
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Adenine nucleotide translocation
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antiport
atp in adp out 1:1 + charge outside from proton grad so - ATP will move out |
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phosphate translocase
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symport
P (H2PO4) and H both into matrix |
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NADH transport into mito
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NADH shuttle mechanism
using malate dehydrogenase oxaloacetate -> malate, this oxidizes NADH malate goes inside cell via malate-aspartate shuttle malate--> oxaloacetate reducing NAD+ SEE PAGE 415 for more detail?? |
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Inhibitors and uncouplers of ox phos
inhibitors: two types and examples |
respiratory inhibitors: act on respiratory chain
CN and CO inhibit cytochrome a3 of complex IV cytochrom oxidase phosphorylation inhibitors: act on enzymes of ATP syn oligomycin blocks Fo of atp synthase |
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uncouplers of ox phos
2 ex |
DNP 2,4-dinitrophenol, weak acid thats protonated in intermembrane space and then diffuses into matrix destroying the [grad]
UCPI (thermogenin) - brown adipose, membrane spanning protein allows influx of protons into mito Note: uncouplers actually INCREASE oxygen consumption |
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ancillary reactions
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energy coupled reactions
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examples of mitochondrial ancillary reactions
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Ca uptake
ATP/ADP exchange NADP+/NADH aa aspartate to cytosol(-?)(possibly, because asp in C of atp synthase when protonated is neutral and thats what causes the turning) |
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Ca ancillary energy coupled reaction
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activates PDH through phosphatase
moves into matrix, since its +charged it dissipates the gradient a little |
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What do high [] of ca do in mito?
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lead to apop through pore formation and release of cytochrome C
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ATP ADP transport
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atp out ADP in, atp is -4, adp is -3 so net neg charge moving out, dissipates pH grad
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ASpartate
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negativly charged, moves out of matrix into cytosol
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NADP+
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reduced by NADH, less NADH means less ETC
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Ancillary rxns
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dont req ATP, use e transport
competes with ATP synthesis stimulates e transport inhibited by respiratory inhibitors and uncouplers, not by phosphorylation inhibitors |
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the three mitochondrial diseases
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LHON
MERRF Exercise intolerance |
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LHON
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lebers hereditary optic neuropathy
complex I decreased activity NADH-ubiquinone oxidoreductase |
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MERRF
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myoclonic epilepsy and ragged red fiber
complex IV cytochrome c oxidase mutation in tRNA |
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excersize intolerance
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not maternal inheritance
cytochrome b mutations somatic in muscle |
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what does released cytochrome c do in apoptosis
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forms apoptosome with factors in cytosol, this activates caspase leading to cell destruction
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