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7 Cards in this Set
- Front
- Back
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where do oxphos & photophos take place, respectively? what major reaction do they involve?
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OxPhos - in mitochondria, involves reduction (NADH & FADH2 are electron donors)
Photophos - in chloroplasts, involves oxidation (NADP+ is final electron acceptor) |
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what are the similar mechnisms b/t them?
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1. promote electron flow by chain of membrane-bound carriers
2. create UPHILL proton transport (generates electrochem potential!) 3. uses DOWNHILL flow of protons to generate ATP |
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name the universal electron carriers
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Nicotinamide Nucleotides: NAD+ & NADP+ (DO NOT CROSS *inner* MITO MEMBRANE)
Flavin Nucleotides: FAD & FMN Ubiquinone (Coenzyme Q) - can accept 1 (semiquinone) or 2 (ubiquinol) electrons, lipid soluble, remains in lipid bilayer Cytochromes - contain Fe heme group (tightly but not covalently assoc. w/ protein), most are integral proteins in INNER mito membrane, 3 classes (a, b, c) Fe-S Proteins: always 1 electron transfers, only one iron is oxidized or reduced in core? |
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name the four protein components of the mitochondrial ETC
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I: NADH:ubiquinone oxidoreductase
II: Succinate dehydrogenase III: Ubiquinone:Cytochrome C oxidoreductase IV: Cytochrome Oxidase |
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Complex I: NADH:Ubiquinone oxidoreductase
- What are the prosthetic groups? - Where to/from are the electrons transferred? - Does it pump protons? |
Prosthetic groups: FMN & Fe-S (6 diff iron centers)
Carrier of NADH to Ubiquinone Pumps 4 H+ for every electron pair out of inner membrane Catalyzed 2 coupled rxns: 1. electron transfer drives: 2. proton pump |
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Inhibitors of Complex I?
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Amytal, Rotenone, Piericidin, all BLOCK ELECTRON FLOW to ubiquinone from Fe-S center
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Complex II: Succinate Dehydrogenase
- What are the prosthetic groups? - Where to/from are the electrons transferred? - Does it pump protons? |
Prosthetic groups: FAD & Fe-S (4 proteins + 2 prosthetic)
the only mem-bound enzyme in kerb's cycle carrier from succinate to ubiquinone does NOT pump protons |
