Electron transport diagram

Note that this cyclic electron-transfer process produces no net oxidation or reduction. However, in the process, protons acquired from the cytoplasm are translocated across the plasma membrane to establish a transmembrane electrochemical potential gradient. The dissipation of such a proton gradient then provides the necessary energy to drive ATP synthesis. A similar simplified cyclic electron-transport diagram has been shown earlier in Chapter 3 as Fig. 12 (C) on p. 81, in coimection with a discussion of a LHl-RC-Cyt6c, supercomplex of Rb. sphaeroides. More detailed discussion of the cytochromeic] and bff complexes and ATP synthesis will be presented in Chapters 35 and 36, respectively. 

Figure 13-1. Encigy level diagrams under forward bias, (a) Single-layer device Iransports both holes and clccu ons and emits (b) iwo-layer device with hole and electron transport layers, one or both of which may emit (c) three-layer device with emitting dye doped (here) into a thin region of the electron transport layer.

Figure 9. Schematic diagrams of (A) parallel-band electrode,141 142 (B) sandwiched electrode,139 140 and (C) rotating-disk voltammetry60 143 methods for making in situ electron transport measurements on polymer films.

Figure 6. Pathways of protons and electrons during mitochondrial oxidations. The diagrams show the pathways of electrons which enter the electron chain at the level ofcomplexi (a)orcomplex II (b). Complexes I, III, and IV usethefreeenergy of electron transport to pump protons out of the matrix. This diagram also distinguishes formally between protons released by dehydrogenation and those which are pumped out of the matrix, although they all enter or leave the same pool.

Fig. 1. Simplified diagram of the section of the electron transport system coupled to cyt c...

Figure 23-32 Simplified diagram of cyclic electron flow in purple bacteria. Two protons from the cytoplasm bind to QB2 in the reaction center to form QH2 (ubiquinol), which diffuses into the ubiquinone pool. From there it is dehydrogenated by the cytochrome kq complex with expulsion of two protons into the periplasm. A third and possibly a fourth proton may be pumped (green arrows) across the membrane, e.g., via the Q cycle (Fig. 18-9). The protons are returned to the cytoplasm through ATP synthase with formation of ATP. Some electrons may flow to the reaction centers from such reduced substrates as S2 and some electrons may be removed to generate NADPH using reverse electron transport.345...

Figure 5.4 Energy diagram of the two linked photosynthetic systems of green plants. The vertical scale is the energy (in eV) of an electron at the various stages of electron transport. P700 (pigment 700) and P680 (pigment 680) are chlorophylls with absorption maxima at 700 nm and 680 nm, respectively...

Figure 8.8 Schematic diagram showing SECM measurement of lateral (in-plane) and cross-film electron transport properties in multilayer polymer/nanoparticle films.30 (Reprinted with permission from V. Ruiz et al., Nano Lett. 2003, 3, 1459-1462. Copyright 2003 American Chemical Society.)...

Fig. 5. (a) Bulk electronic concentration at the metal—oxide interface and electron-hole concentration at the oxide—oxygen interface associated with equilibrium interfacial reactions, (b) Electronic energy-level diagram illustrating the dielectric (or semiconducting) nature of the oxide, with the possibility of electron transport (e.g. by tunneling or thermal emission) from the metal to fill O levels at the oxide—oxygen interface to create a potential difference, VM, across the oxide. 

Fig. 13. Possible sign combinations involving the sign of the surface charge at the metal—oxide interface and the sign of the charge of the field-driven mobile species originating at the metal—oxide interface, together with schematic diagrams of the concentration profiles for the mobile species, (a) Field-driven cation interstitial (or anion vacancy) transport (b) Field-driven electron transport.

As seen in Figure 8-4, disruption in the flow of electrons through the ETC can lead to an increase in NADH depending on the location of the block in electron transport. The increase in NADH will shut down the TCA cycle via specific inhibition of key TCA enzymes by NADH. The buildup of NADH will thus result in depletion of NAD+ stores. How are the NAD+ levels restored The NADH is used to reduce pyruvate to lactate, as indicated in the following diagram ... 

Figure 3. Schematic diagram of an apparatus for measuring transmembrane oxidation-reduction in a planar bilayer membrane. The mechanism described is simple carrier-mediated electron transport. D = aqueous electron donor A = aqueous electron acceptor ...

Figure 3. Diagram of a section through the cell wall of Acidithiobacillus ferrooxidans modified from Blake et al. (1992) showing the relationship between iron oxidation and pyrite dissolution. OM =outer membrane, P = periplasm, IM = inner or (cytoplasmic) membrane, cty = cytochrome, pmf = proton motive force. Passage of a proton (driven by proton motive force) into the cell catalyzes the conversion of ADP to ATP. Ferrous iron binds to a component of the electron transport chain, probably a cytochrome c, and is oxidized. The electrons are passed to a terminal reductase where they are combined with O2 and to form water, preventing acidification of the cytoplasm. Ferric iron can either oxidize pyrite (e.g. within the ore body) or form nanocrystalline iron oxyhydroxide minerals (often in surrounding groundwater or streams).

Diagram of the functional complexes of the electron transport system within the respiratory chain. Fnad = NADH dehydrogenase flavoprotein Fs = succinate dehydrogenase flavoprotein Fefn.h.) = nonheme iron. 

Transfer of HVe" pairs to electron transport carriers, decarboxylation, and substrate-level phosphorylation occur at some of the steps shown in the following diagram ol the citric acid cycle. All three of these events occur at which step ... 

Figure 16-1. Schematic diagram of electron transport chain ATP synthase and ATP/ADP translocase.

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