Why is nadp important in photosynthesis

Recall that NADH was a similar molecule that carried energy in the mitochondrion from the citric acid cycle to the electron transport chain. This potential energy is harvested and stored as chemical energy in ATP through chemiosmosis, the movement of hydrogen ions down their electrochemical gradient through the transmembrane enzyme ATP synthase, just as in the mitochondrion.

The hydrogen ions are allowed to pass through the thylakoid membrane through an embedded protein complex called ATP synthase. The energy generated by the hydrogen ion stream allows ATP synthase to attach a third phosphate to ADP, which forms a molecule of ATP in a process called photophosphorylation.

The flow of hydrogen ions through ATP synthase is called chemiosmosis just like in cellular respiration , because the ions move from an area of high to low concentration through a semi-permeable structure. The remaining function of the light-dependent reaction is to generate the other energy-carrier molecule, NADPH. As the electron from the electron transport chain arrives at photosystem I, it is re-energized with another photon captured by chlorophyll.

Now that the solar energy is stored in energy carriers, it can be used to make a sugar molecule. The pigments of the first part of photosynthesis, the light-dependent reactions, absorb energy from sunlight.

A photon strikes the antenna pigments of photosystem II to initiate photosynthesis. The energy travels to the reaction center that contains chlorophyll a to the electron transport chain, which pumps hydrogen ions into the thylakoid interior the lumen. This action builds up a high concentration of hydrogen ions.

The ions flow through ATP synthase via chemiosmosis to form molecules of ATP, which are used for the formation of sugar molecules in the second stage of photosynthesis. Photosystem I absorbs a second photon, which results in the formation of an NADPH molecule, another energy and reducing power carrier for the light-independent reactions. Unless otherwise noted, images on this page are licensed under CC-BY 4. Text adapted from: OpenStax , Concepts of Biology.

OpenStax CNX. Skip to content Photosynthesis takes place in two stages: the light-dependent reactions and the Calvin cycle. Hydrogen ions are transported with the electrons along the chain of reactions. The second stage of photosynthesis uses carbon dioxide to produce molecules of glucose. These reactions do not need light energy to proceed and are sometimes called the light-independent reactions. The Calvin cycle adds one molecule of carbon dioxide at a time, so it must repeat to synthesize the six-carbon structure of glucose.

The NADPH produced in the light-dependent stage of photosynthesis provides the chemical energy to fuel the Calvin cycle and keep it going. Adenosine triphosphate , or ATP, is another molecule produced when light energy is converted to chemical energy via the electron transport chain. ATP forms when a phosphate group is added to ADP, adenosine diphosphate, in a process called photophosphorylation. The hydrogen ions freed by the breakdown of water molecules flow through an enzyme called ATP synthase.

She worked as a researcher and analyst in the biotech industry and a science editor for an educational publishing company prior to her career as a freelance writer and editor. Alissa enjoys writing about life science and medical topics, as well as science activities for children.

Describe What a Photosystem Does for Photosynthesis. Nucleic Acids Research. Proteins: Structure, Function and Bioinformatics. Model building by comparison at CASP3: using expert knowledge and computer automation. Arabidopsis Tic62 and ferredoxin-NADP H oxidoreductase form light-regulated complexes that are integrated into the chloroplast redox poise.

The Plant Cell. The focusing positions of polypeptides in immobilized pH gradients can be predicted from their amino acid sequences. Sequence and structure-based prediction of eukaryotic protein phosphorylation sites.

Molecular Biology. Manganese superoxide dismutase can reduce cellular damage mediated by oxygen radicals in transgenic plants. EMBO Journal. Redox modulation of cyclic electron flow around photosystem I in C3 plants. Alternative photosystem I-driven electron transport routes: mechanisms and functions.

Photosynthesis Research. Blue silver: a very sensitive colloidal Coomasie G staining for proteome analysis. European Biochemistry. Plant Physiology. Photosystem I: function and physiology. FEBS Letters. Photosystem I cyclic electron transport: measurement of ferredoxin-plastoquinone reductase activity. Domain fishing: a first step in protein comparative modelling. Plasticity in light reactions of photosynthesis for energy production and photoprotection.

Journal of Experimental Botany. Growth and photosynthesis in first leaf of barley — effect of time of application of nitrogen. Annals of Botany. ChloroP, a neural network-based method for predicting chloroplast transit peptides and their cleavage sites. Protein Science. Locating proteins in the cell using TargetP, SignalP, and related tools.

Nature Protocols. Rubiscolytics: fate of Rubisco after its enzymatic function in a cell is terminated. Characterizing phosphoproteins and phosphoproteomes using mass spectrometry. Briefings in Functional Genomics and Proteomics. Photosynthetic electron transport in higher plants. Annual Review of Plant Physiology. Altered photosynthetic electron channelling into cyclic electron flow and nitrate assimilation in a mutant of ferredoxin:NADP H reductase. Plant, Cell and Environment. Multiple iso-proteins of FNR in Arabidopsis : evidence for different contributions to chloroplast function and nitrogen assimilation.

Biochem Biophy Res Com. Plant Science. Biochimica et Biophysica Acta. Proteins flex to function. The Plant Journal. Protein import into chloroplasts involves redox-regulated proteins. Observations on the mechanism of chloroplast division in higher plants.

New Phytologist. Journal of Biological Chemistry. Electron transport pathways in spinach chloroplasts. Reduction of the primary acceptor of photosystem II by reduced nicotinamide adenine dinucleotide phosphate in the dark. Cyclic electron flow around photosystem I is essential for photosynthesis.

PGR5 is involved in cyclic electron flow around photosystem I and is essential for photoprotection in Arabidopsis. Plant Molecular Biology. Scansite 2. Calibration of simultaneous measurements of photosynthetic carbon dioxide uptake and oxygen evolution in leaves. Plant and Cell Physiology. Three maize leaf ferredoxin:NADPH oxidoreductases vary in subchloroplast location, expression, and interaction with ferredoxin. Effects of nitrogen and phosphorus deficiencies on levels of carbohydrates, respiratory enzymes and metabolites in seedlings of tobacco and their response to exogenous sucrose.

Probability-based protein identification by searching sequence databases using mass spectrometry data. BMC Bioinformatics. In-gel digestion for mass spectrometric characterization of proteins and proteomes. Mass spectrometric sequencing of proteins from silver-stained polyacrylamide gels. Analytical Chemistry. Proteolytic degradation of ferredoxin NADP reductase during protein purification from spinach.

Archives of Biochemistry and Biophysics. Protein import into chloroplasts: new aspects of a well-known topic. Biological Chemistry. Subcellular fractionation of plant tissues. Isolation of plastids and mitochondria. Methods in Molecular Biology. Development of photorespiration during chloroplast biogenesis in wheat leaves. Enhancement of oxidative stress tolerance in transgenic tobacco plants overproducing Fe-superoxide dismutase in chloroplasts.

Support Center Support Center. External link. Please review our privacy policy.