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26 Cards in this Set
- Front
- Back
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What complexes in the ETC pump protons? |
I, III, IV |
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What is the inner and outer mito membrane permeable to? |
outer - permeable to small molecules inner - impermeable (except O2, CO2, NH3, H2O) |
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What are the complexes and their names? |
I - NADH dehydrogenase II - succinate dehydrogenase CoQ - Q10 or ubiquinone III - cyt-bc1 cyt-c IV - cyt c oxidase |
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FADH2 can come from where through complex II? |
-TCA -FA oxidation (fatty acyl-CoA DH- matrix -Mito G3P DH of glycerol- intermembrane space |
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Describe structure of ATP synthase |
f1 - in matrix (rotational energy allows synthesis of ATP) f0 - inner membrane contains proton pore |
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Where does ADP come from? |
ADP/ATP antiport - pump ADP into matrix so can enter synthase (driving force is protons so don't wastefully put ADP into matrix) |
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What happens to the ETC during hypoxia? |
hypoxia--> decreased ETC --> decreased ATP --> Increased Na+ --> cell swelling --> increased plasma membrane permeability decreased ATP/cell swelling/increased permeability --> increased Ca (mito permeability -- cell death) |
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What is atractyloside? |
Inhibits ATP/ADP antiporter - can't get ADP in matrix and ATP in intermembrane space --> stops ATP synthesis and ETC (bc of buildup of proton gradient) |
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Amytal |
-barbiturate -treatment for anxiety, epilepsy, insomnia -reversible inhibitor of NADH DH -protect cardiac muscle during ischemia by limiting ROS |
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Rotenone |
-naturally occurring pesticide (aka fish poison) -potent inhibitor of NADH DH -no NADH can be oxidized, but succinate can enter leading to reduced ATP production |
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Antimycin/antifungal (agriculture) |
-inhibitor of complex III - binds tightly to cyt b in reduced state -I, CoQ, II fully reduced -Cyt c, IV fully oxidized -no ATP - stops ETC |
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CN- |
-binds to oxidized form of heme iron (ferric state) of cyt oxidase a3 --> complex IV cannot be reduced -no ATP - cell death |
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How do you treat CN- poisoning? |
Nitrate followed by thiosulfate treatment -nitrate converts Hb iron to ferric--> MetHb (high affinity for CN-) -add thiosulfate and enzyme rhodanese --> SCN- + SO3 (hydrophillic - excreted) |
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Carbon Monoxide |
-competes with O2 for binding to reduced heme-a3 in complex IV (Fe2+ form) -more poisoning thru CO by also Hb binding |
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Oligomycin |
-binds to F0 portion - blocks proton pathway and prevents reentry of protons into matrix -no ATP and proton gradient builds up |
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What occurs as a result of uncouplers / reduction of proton gradient? |
-respiratory rate is fast (no longer controlled by ADP/ATP) -rate of respiration is limited only by availability of NADH, succinate, and O2 -acceleration of TCA and electron transfer to O2 -inhibition of ATP synthase -generation of heat due to flow of protons into matrix |
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AraC, AZT |
-AraC (chemo) and AZT (HIV) - uncoupler by causing membrane damage to dissipate gradient |
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DNP, aspirin |
-uncouplers -very lipophillic and weak bases - grab proton within intermembrane space and carry it to matrix - dissipating gradient |
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Thermogenin / UCP-1 |
-uncoupler - proton channel -found in BAT of humans/hibernating animals + newborns -adults --> homeostasis -newborns --> exclusively heat generation |
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BAT vs WAT |
BAT- thermogenic, many mito, vascularized, UCP-1 WAT - non-therm, few mito/capillaries, leptin |
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What increases UCP1 expression? |
-cold -SNS -fatty acids within BAT activate UCP |
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Where is the malate-aspartate shuttle used? |
-heart, kidney, liver -transports cytoplasmic NADH into matrix -ONLY works if (NADH/NAD+) is higher in cytoplasm than matrix -reversible -1 NADH --> 3 ATP |
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Describe malate-aspartate shuttle |
1. NADH made in cytosol --> give 2e- to oxaloacetate to make malate (via cytoplasmic malate DH) 2. Malate gets into matrix 3. In matrix, malate gives 2e- to NAD+ --> NADH and oxaloacetate (via mito malate DH) 4. recycle oxaloacetate --> alpha-KG (via AST) 5. alpha-KG crosses into cytosol and becomes oxaloacetate via AST |
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How is oxaloacetate --> alpha-KG? |
-oxaloacetate + glutamate (via AST) --> aspartate + alpha-KG |
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Where is the glycerol phosphate shuttle used? |
-skeletal muscle, brain --> don't want to depend on conc gradient/run all the time -irreversible -1 NADH --> 2 ATP via FADH2 -can be used under all conditions |
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Describe glycerophosphate shuttle |
1. NADH in cytosol gives electrons to DHAP --> glycerol 3-P 2. goes to glycerol 3-P DH --> makes FADH2 and DHAP 3. FADH2 goes directly to CoQ of ETC |
