BioChem: METC

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In the electron transport chain, what does it do overall in terms of reoxidizing?: -it reoxidizes the coenzymes reduced in glycolysis and the TCA cycle
What are the 4 complexes of the ETC?: 1) NADH-Ubiquinone Oxidoreductase
2) Succinate - Ubiquinone Oxidoreductase
3) Ubiquinol - Cytochrome C Oxidoreductase
4) Cytochrom C Oxidase
How are electrons passed through Complex 1?: -elctrons from NADH to FMN
-then to a series of Fe-S proteins
-Lastly passed to Ubiquinone
How many electrons can NADH carry? FMN? Fe-S proteins? Ubiquinone?: -2
-1 or 2
-1
-2
What are the two possible centers of Iron-Sulfate proteins?: -2FE-2S or 4Fe-4S complexes
What was the case of 'Living Statues"?: -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
Describe MPP in the body.: -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
What is dopamines role in Parkinson treatment?: -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
What is Complex II also known as?: -Succinate Dehydrogenase (from TCA cycle)
Describe what Complex II does?: -contains a covalentrly bound FAD and two Fe-S proteins
-also transfers electrons to Ubiquinone (like C-I)
Describe Complex III.: -passes electrons from reduced Ubiquinone to Cytochrome C
What are cytochromes?: -small membrane associated proteins with a heme
--different classes have different substitutions on the heme group
Spectromphotomically, how can you tell cytochromes apart?: -when reduced, they have different absorbancies
What does Complex IV do?: -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)
How many electrons does the reduction of Oxygen require?: -4 electrons
*copper and heme iron can only handle 1 electron
What are the parts 1 and 2 (of 4) of the Chemiosmotic Hypothesis?: 1) mitochondrial inner membrane (MIM) is impermeable to H+
2) MIM has carrier proteins to mediate entry/exit of metabolites
What is part 3 of the Chemiosmotic Hypothesis?: 3) ETC is proton-translocating and pumps H+ out of matric space when electrons are transported
What is the 4th part of Chemiosmotic Hypothesis?: 4) mitochondrial ATP synthase complex also translocates protons across membrane. It can use the energy of proton gradient to drive ATP synthsis
What are 4 peices of evidence for the Chemiosmotic theory?: - 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
In respiration of mitochondria, what two things are coupled?: -oxidation of substrates
-phosphorylation of ADP
What must be present for respiration to proceed in Mitochonrion?: -ADP must be present
*amount of O2 consumed depends upon the amount of ADP added
What does Uncoupler DNP do?: -allows for O2 consumption without ADP
Describe Uncouplers.: -allow for O2 consumption without ADP
-lipid-soulbe weak acids
-can cross MIM
-deplete any proton gradient by transporting protons across the membrane
Give an example of a common Uncoupler.: -2.4-Dinitrophenol
Why can both acidic and Basic forms of DNP dissolve in the membrane?: -becuase negative charge is delocalized over the ring
What is Mitochondrial Inner Membrane ATPase for?: -treatment on inside-out particles to give free F1
-Part remaining in membrane is F0
What does F1 do?: -hydrolizes ATP (can NOT synthesize ATP)
What does F0 do?: -catalyze proton transport (can NOT synthesize ATP)
What does F1F0 ATPase do?: -Haloenzyme that uses proton motive force to convert ADP back to ATP
What are two Mitochondrial diseases?: -Leber's Hereditary Optic Neurophothy (LHON)
-Mutations in Cytochrome b
Describe Hereditary Optic Neurophathy (LHON).: -causes sudden-onset blindness
-mutation in mitochondrial DNA for proteins in electron transport complex I
-can cause dystonia
Describe mutations of Cytochrome b.: -exercise intolerance, lactic acidosis in resting state and myoglobinuria
-somatic mutation in the gene for cytochrome B

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