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23 Cards in this Set
- Front
- Back
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What is step 1 of TCA?
1. Reaction 2. Enyzme involved and Function 3. Type of Reaction |
1. condensation of Acetyl CoA with oxaloacetate
2. Citric Synthase - allosteric enzyme, inhibited by NADH, ATP, and Succ-CoA 3. Hydrolysis provides energy to drive Step 1 |
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What is step 2 of TCA?
1. Reaction 2. Enzyme 3. Type |
1. Citrate --> Aconitate --> Isocitrate
2. Aconitase - makes aconitate --> Isocitrate 3. Dehydration of Citrate --> Aconitate and Rehydration of Aconitate --> Isocitrate Isocitrate is chiral while other two are not, only 1 of its 4 steroisomers is formed in the cycle |
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What is step 3 of TCA?
1. Reaction 2. Enzyme 3. Type |
1. Isocitrate --> Oxalosuccinate --> Alpha-Ketoglutarate
2. Isocitrate dehydrogenase - allosteric enzyme; inhibited by ATP and NADH, activated by ADP and NAD+ 3. Oxidation of Isocitrate and decarboxylation of alpha-ketoglutarate |
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What is step 4 of TCA?
1. Reaction 2. Enzyme 3. Type |
1. Alpha-ketoglutarate --> Succinyl-CoA + CO2
2. Alpha-ketoglutarate dehydrogenase complex - inhibited by ATP, NADH, and Suc-CoA, activated by ADP and NAD+ 3. Oxidative decarboxylation |
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What is step 5 of TCA?
1. Reaction 2. Enzyme 3. Type |
1. Succ-CoA + GDP + Pi --> Succinate + GTP + CoA-SH
2. Succ-CoA synthetase 3. Energy yielding reaction, GTP produced |
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What are steps 6 and 7 of TCA?
1. Reaction 2. Enzyme 3. Type |
6:
1. Succinate --> Fumarate 2. Succinate dehydrogenase 3. Oxidation (FAD --> FADH2) 7: 1. Fumarate --> L-Malate 2. Fumarase 3. Hydration |
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What is step 8 of TCA?
1. Reaction 2. Enzyme 3. Type |
1. L-Malate --> Oxaloacetate
2. Malate dehydrogenase 3. Oxidation (NAD --> NADH) Oxaloacetate then reacts with Acetyl CoA to start step 1 again |
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What are the overall products of the TCA cycle?
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2 carbon dioxides
1 CoA 1 GTP 3 NADH 1 FADH2 3 H+ |
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What are the 3 enzymes that control the cycle?
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Citrate synthase - inhibited by ATP, NADH, and Succ-CoA
Isocitrate dehydrogenase - activated by ADP and NAD+, inhibited by ATP and NADH Alpha-Ketoglutarate dehydrogenase complex - inhibited by ATP, NADH, and Succ-CoA; activated by ADP and NAD+ |
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What are the inhibitors of Complex I (Cyt Q) in Respiratory chain?
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Amobarbital - barbiturate, sedative
Pericidin A - antibiotic Rotenone - insecticide and fish poison, not fatal but causes vomiting |
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What are the inhibitors of Complex II (Cyt Q) in Respiratory chain?
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Carboxin
Malonate - competitive inhibitor of Succinate Dehydrogenase |
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What are the inhibitors of Complex III (Cyt C) in Respiratory Chain?
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Dimercaprol
Antimycin A |
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What are the inhibitors of Complex IV in Respiratory Chain?
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H2S (dihydrogen sulfide)
Carbon Monoxide (CO) Cyanide |
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What are some inhibitors of Oxidative Phosphorylation?
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Atractyloside - inhibits translocation of ADP and ATP
Oligomycin - inhibits ATP synthase blocks the FoF1 ATPase blocks conduction of H+ through F0 Prevents ATP manufacture, with decreased oxygen consumption |
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What are uncouplers and examples?
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leakage of H+ across membrane collapsing electrochemical proton gradient
dissociate oxidation from phosphorylatoin examples: 2,4 dinitrophenol dinitrocresol pentachlorophenol chlorocarbanoyl cyanide phenylhydrazone |
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What does 2,4 dinitrophenol do?
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diffuses across inner mitochondrial membrane and loses energy as heat
causes ETC to proceed at rapid rate w/o production of proton gradient example of a thermogenin - brown adipose tissue and a natural uncoupler |
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What is Brown Adipose Tissue (Brown Fat) characterized by?
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well developed blood supply
high content of mitochondria and cytochromes low activity of ATP synthase energy produced by ETC is dissipated as heat instead of producing ATP oxidation and phosphorylation are not coupled active in species in arousal from hibernation in humans: infants have a lot, not adults genetically predisposed individuals have large amounts "eat and not get fat" |
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What are ionophores?
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lipophilic
transport specific cations through membranes eliminates membrane potential and pH gradient causing inhibition of phosphorylation dinitrophenol is a proton ionophore |
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What are the 3 electron driven pumps?
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NADH-Q-oxidoreductase - NADH --> Q
Q-cytochrome c oxidoreductase - Q --> Cyt C cytochrome c oxidase - Cyt c --> O- |
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What does Complex I do?
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large complex
oxidizes NADH --> NAD+ oxidizing agent is Cyt Q which is reduced to CoQH2 some of the energy released in oxidation of NAD+ is used to move 2H+ from matrix into intramembrane space |
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What does Complex II do?
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oxidizes FADH2 --> FAD
oxidizing agent is CoQ, which is reduced to CoQH2 |
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What does Complex III do?
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delivers electrons from CoQH2 to cytochrome c
has two channels through which the two H+ from each CoQH2 oxidized are pumped from the matrix into the inramembrane space |
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What does Complex IV do?
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known as cytochrome oxidase
electrons flow from cyt c in III to cyt A3 in IV from Cyt A3 electrons transferred to O2 during this redox reaction, H+ are pumped from matrix into intermembrane space |
