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Nicotinamide adenine dinucleotide phosphate, abbreviated NADP [1] [2] or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent ('hydrogen source'). NADPH is the reduced form, whereas NADP + is the ...
The actual concentration of NAD + in cell cytosol is harder to measure, with recent estimates in animal cells ranging around 0.3 mM, [18] [19] and approximately 1.0 to 2.0 mM in yeast. [20] However, more than 80% of NADH fluorescence in mitochondria is from bound form, so the concentration in solution is much lower.
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 ...
The cooperation between Photosystems I and II creates an electron and proton flow from H 2 O to NADP +, producing NADPH needed for glucose synthesis. This pathway is called the 'Z-scheme' because the redox diagram from H 2 O to NADP + via P680 and P700 resembles the letter Z. [11]
The ratio of NADPH:NADP + is the primary mode of regulation for the enzyme and is normally about 100:1 in liver cytosol [citation needed]. This makes the cytosol a highly-reducing environment. An NADPH-utilizing pathway forms NADP +, which stimulates Glucose-6-phosphate dehydrogenase to produce more NADPH.
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.
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 .
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.