Photosystem summary

See also Photosystem I, Photosystem Summary, Chlorophyll, Light Harvesting Complex, Figure... 

See also Calvin Cycle, Photosystem II, Photosystem I, Photosystem Summary, Carbohydrates (from chapter 9), NADPH, The Energy of Light, Photochemistry... 

See also , Photosystem Summary, Cyclic Electron Flow, Chlorophyll, Reaction Center, FNR, Figure 17.16... 

See also Photoreactivation, Photochemistry, Photosystem Summary, Pyrimidine Dimers, Thymine Dimers, Tetrahydrofolate Coenzymes... 

See also Pyrimidine Dimers, O -Alkylguanine Alkytransferase, Types and Consequences of DNA Damage, Light Absorbing Pigments (from Chapter 17), Photochemistry (from Chapter 17), Photosystem Summary (from Chapter 17)... 

See also Ferredoxin, Figure 17.12b, Photosystem II, Photosystem Summary,... 

Photosystem I Photosystem Summary Cyclic Electron Flow Calvin Cycle... 

This summary reveals the mechanistic complexity of C02-fixation processes using homogeneous catalysts. Formation of C02 insertion products into hydrido-metal intermediates could lead to metal-carboxylate or metal-formate species. At this stage it is impossible to elucidate the detailed mechanistic profiles of these transformations. In the photosystem that applies/ac-Re(bpy)(CO)3X as catalyst, O II... 

We shall now turn our attention to the specific molecules that act as electron acceptors or donors in chloroplasts. A summary of the characteristics of the most common components of this complex pathway is presented in Table 5-3. Figure 6-4 should also be consulted, if the underlying concept of redox potential is already familiar. We will begin our discussion by considering the photochemistry at the reaction center of Photosystem II and then consider the various substances in the sequence in which they are involved in electron transfer along the pathway from Photosystem II to Photosystem I. We will conclude by considering the fate of the excited electron in Photosystem I. 

The herbicidal activity of 1,1-dimethyl-4,4 -dimethylbipyridylium dication ( Paraquat ) seems to depend on the formation of the cation radical through reaction with a component of photosystem 1 in the chloroplast, followed by reaction with oxygen to form superoxide ion (Eq, 36) (for a summary of references, see >). The rate constant for the latter reaction has been reported... 

Fig. 6, Summary of the evolution of ideas of the molecular organization of the photosystems in thy-lakoid membranes.

Table I. Summary of photosystem-l peripheral light-harvesting proteins fractionated from spinach and barley as designated In different nomenclatures, and names of their assigned genes and gene products...

Fig. 6. Summary of the standard oxidation-reduction potentials of several dyes and the experimentally determined rate constants for their reduction by P430 . [DP, dipyridyls, preceded by the redox-potential values M(B)V, methyl (benzyl) viologens ST. safranine T MB, methylene blue]. Figure source Ke (1973) The primary electron acceptor of photosystem I. BiochimBiophysActa301 29.

Summary Thylakoids of vegetative cells of Anabaena variabilis use both NADH and NADPH for (dark) respiration in a cyanide-sensitive reaction. Both nucleotides also function as donors for photosystem I in the light and in the presence of DCMU. Double-reciprocal plot analysis yields different Kjn- and Vm x alues in the dark and in the light for NADPH and NADH. An interaction of respiratory and photosynthetic electron transport is obvious, using NADH as reductant, since a different dehydrogenase activity is evident in the dark, as compared with the activity in the light with DCMU and KCN present. 

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