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  2. Photophosphorylation - Wikipedia

    en.wikipedia.org/wiki/Photophosphorylation

    It is necessary either to supply an activation energy or to lower the intrinsic activation energy of the system, in order to make most biochemical reactions proceed at a useful rate. Living systems use complex macromolecular structures to lower the activation energies of biochemical reactions.

  3. Fractionation of carbon isotopes in oxygenic photosynthesis

    en.wikipedia.org/wiki/Fractionation_of_carbon...

    Under kinetic conditions, such as an enzymatic reaction with RuBisCO, the lighter isotope is favored because of a lower activation energy. Oxygenic photosynthesis is a metabolic pathway facilitated by autotrophs, including plants, algae, and cyanobacteria. This pathway converts inorganic carbon dioxide from the atmosphere or aquatic environment ...

  4. Calvin cycle - Wikipedia

    en.wikipedia.org/wiki/Calvin_cycle

    The enzymes in the Calvin cycle are functionally equivalent to most enzymes used in other metabolic pathways such as gluconeogenesis and the pentose phosphate pathway, but the enzymes in the Calvin cycle are found in the chloroplast stroma instead of the cell cytosol, separating the reactions. They are activated in the light (which is why the ...

  5. Photosystem II - Wikipedia

    en.wikipedia.org/wiki/Photosystem_II

    The energized electrons transferred to plastoquinone are ultimately used to reduce NADP + to NADPH or are used in non-cyclic electron flow. [1] DCMU is a chemical often used in laboratory settings to inhibit photosynthesis. When present, DCMU inhibits electron flow from photosystem II to plastoquinone.

  6. Ferredoxin-thioredoxin reductase - Wikipedia

    en.wikipedia.org/wiki/Ferredoxin-thioredoxin...

    It catalyses the light-dependent activation of several photosynthesis enzymes and constitutes the first historical example of a thiol/disulfide exchange cascade for enzyme regulation. [1] It is a heterodimer of subunit alpha and subunit beta. Subunit alpha is the variable subunit, and beta is the catalytic chain.

  7. Photorespiration - Wikipedia

    en.wikipedia.org/wiki/Photorespiration

    Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts, leaf peroxisomes and mitochondria. The oxygenation reaction of RuBisCO is a wasteful process because 3-phosphoglycerate is created at a lower rate and higher metabolic cost compared with RuBP carboxylase activity.

  8. Ferredoxin—NADP(+) reductase - Wikipedia

    en.wikipedia.org/wiki/Ferredoxin—NADP(+)_reductase

    The 3 substrates of this enzyme are reduced ferredoxin, NADP +, and H +, whereas its two products are oxidized ferredoxin and NADPH. It has a flavin cofactor, FAD. This enzyme belongs to the family of oxidoreductases, that use iron-sulfur proteins as electron donors and NAD + or NADP + as electron acceptors. This enzyme participates in ...

  9. Light-dependent reactions - Wikipedia

    en.wikipedia.org/wiki/Light-dependent_reactions

    The electron in the higher energy level is unstable and will quickly return to its normal lower energy level. To do this, it must release the absorbed energy. This can happen in various ways. The extra energy can be converted into molecular motion and lost as heat, or re-emitted by the electron as light (fluorescence).