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32 Cards in this Set
- Front
- Back
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In the electron transport chain, what does it do overall in terms of reoxidizing?
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-it reoxidizes the coenzymes reduced in glycolysis and the TCA cycle
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What are the 4 complexes of the ETC?
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1) NADH-Ubiquinone Oxidoreductase
2) Succinate - Ubiquinone Oxidoreductase 3) Ubiquinol - Cytochrome C Oxidoreductase 4) Cytochrom C Oxidase |
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How are electrons passed through Complex 1?
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-elctrons from NADH to FMN
-then to a series of Fe-S proteins -Lastly passed to Ubiquinone |
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How many electrons can NADH carry?
FMN? Fe-S proteins? Ubiquinone? |
-2
-1 or 2 -1 -2 |
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What are the two possible centers of Iron-Sulfate proteins?
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-2FE-2S or 4Fe-4S complexes
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What was the case of 'Living Statues"?
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-Heroin users who used a certain synthetic heroin became frozen with advanced stages of Parkinsons Disease
-this was from MPTP in the synthetic being converted to MPP -MPP attacked the substantia nigra degrading the cells rapidly |
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Describe MPP in the body.
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-a powerful inhibitor of Complex I in the mitochonrial ETC
-attacks the substantia nigra part of the brain -Parkinson's patients have the same deterioration, but much slower |
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What is dopamines role in Parkinson treatment?
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-brain cells can no longer produce dopamine, so injections can be given to provide it
-it allows for smooth muscle control/movement. w/o it, muscles are rigid and hard to control |
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What is Complex II also known as?
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-Succinate Dehydrogenase (from TCA cycle)
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Describe what Complex II does?
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-contains a covalentrly bound FAD and two Fe-S proteins
-also transfers electrons to Ubiquinone (like C-I) |
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Describe Complex III.
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-passes electrons from reduced Ubiquinone to Cytochrome C
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What are cytochromes?
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-small membrane associated proteins with a heme
--different classes have different substitutions on the heme group |
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Spectromphotomically, how can you tell cytochromes apart?
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-when reduced, they have different absorbancies
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What does Complex IV do?
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-transfers electron from Cytochrome C to Oxygen
-three largest proteins are coded for in the mitochondrial DNA -these three proteins contain the copper ions and two iron cofactors (cytochromes a and a3) |
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How many electrons does the reduction of Oxygen require?
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-4 electrons
*copper and heme iron can only handle 1 electron |
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What are the parts 1 and 2 (of 4) of the Chemiosmotic Hypothesis?
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1) mitochondrial inner membrane (MIM) is impermeable to H+
2) MIM has carrier proteins to mediate entry/exit of metabolites |
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What is part 3 of the Chemiosmotic Hypothesis?
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3) ETC is proton-translocating and pumps H+ out of matric space when electrons are transported
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What is the 4th part of Chemiosmotic Hypothesis?
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4) mitochondrial ATP synthase complex also translocates protons across membrane. It can use the energy of proton gradient to drive ATP synthsis
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What are 4 peices of evidence for the Chemiosmotic theory?
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- mit. membranes can establich proton gradient
- intact MIM is required for oxidative phosphorylation - key electron transport proteins spand the inner membrane - Uncouplers act by dissipating the proton gradient |
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In respiration of mitochondria, what two things are coupled?
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-oxidation of substrates
-phosphorylation of ADP |
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What must be present for respiration to proceed in Mitochonrion?
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-ADP must be present
*amount of O2 consumed depends upon the amount of ADP added |
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What does Uncoupler DNP do?
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-allows for O2 consumption without ADP
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Describe Uncouplers.
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-allow for O2 consumption without ADP
-lipid-soulbe weak acids -can cross MIM -deplete any proton gradient by transporting protons across the membrane |
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Give an example of a common Uncoupler.
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-2.4-Dinitrophenol
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Why can both acidic and Basic forms of DNP dissolve in the membrane?
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-becuase negative charge is delocalized over the ring
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What is Mitochondrial Inner Membrane ATPase for?
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-treatment on inside-out particles to give free F1
-Part remaining in membrane is F0 |
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What does F1 do?
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-hydrolizes ATP (can NOT synthesize ATP)
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What does F0 do?
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-catalyze proton transport (can NOT synthesize ATP)
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What does F1F0 ATPase do?
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-Haloenzyme that uses proton motive force to convert ADP back to ATP
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What are two Mitochondrial diseases?
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-Leber's Hereditary Optic Neurophothy (LHON)
-Mutations in Cytochrome b |
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Describe Hereditary Optic Neurophathy (LHON).
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-causes sudden-onset blindness
-mutation in mitochondrial DNA for proteins in electron transport complex I -can cause dystonia |
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Describe mutations of Cytochrome b.
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-exercise intolerance, lactic acidosis in resting state and myoglobinuria
-somatic mutation in the gene for cytochrome B |
