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Like the pentose phosphate pathway, these pathways are related to parts of glycolysis. [3] Another carbon metabolism-related pathway involved in the generation of NADPH is the mitochondrial folate cycle, which uses principally serine as a source of one-carbon units to sustain nucleotide synthesis and redox homeostasis in mitochondria.
C 4 carbon fixation has evolved in at least 62 independent occasions in 19 different families of plants, making it a prime example of convergent evolution. [ 19 ] [ 20 ] This convergence may have been facilitated by the fact that many potential evolutionary pathways to a C 4 phenotype exist, many of which involve initial evolutionary steps not ...
Photosynthesis usually refers to oxygenic photosynthesis, a process that produces oxygen. Photosynthetic organisms store the chemical energy so produced within intracellular organic compounds (compounds containing carbon) like sugars, glycogen , cellulose and starches .
In contrast, the main function of NADPH is as a reducing agent in anabolism, with this coenzyme being involved in pathways such as fatty acid synthesis and photosynthesis. Since NADPH is needed to drive redox reactions as a strong reducing agent, the NADP + /NADPH ratio is kept very low. [62]
The chemical pathway of oxygenic photosynthesis fixes carbon in two stages: the light-dependent reactions and the light-independent reactions.. The light-dependent reactions capture light energy to transfer electrons from water and convert NADP +, ADP, and inorganic phosphate into the energy-storage molecules NADPH and ATP.
NADP + + 2H + + 2e-→ NADPH + H + This consumes the H + ions produced by the splitting of water, leading to a net production of 1/2O 2, ATP, and NADPH + H + with the consumption of solar photons and water. The concentration of NADPH in the chloroplast may help regulate which pathway electrons take through the light reactions.
In cyclic photophosphorylation, cytochrome b 6 f uses electrons and energy from PSI to create more ATP and to stop the production of NADPH. Cyclic phosphorylation is important to create ATP and maintain NADPH in the right proportion for the light-independent reactions. The net-reaction of all light-dependent reactions in oxygenic photosynthesis ...
Ferredoxin: NADP + reductase is the last enzyme in the transfer of electrons during photosynthesis from photosystem I to NADPH. [2] The NADPH is then used as a reducing equivalent in the reactions of the Calvin cycle. [2] Electron cycling from ferredoxin to NADPH only occurs in the light in part because FNR activity is inhibited in the dark. [11]