PhotosynthesisPhotosystemsPhotosystem IIComplexesP680FluorescenceProteinAcceptorEfficiencyProtonsQuinoneFlow of electronsElectron transDonor sideRedoxAbsorptionAbsorbsElectrons from waterAntennaMoleculesLHCIIPhotonChloroplastsReductionVivoComplexExcitationLeaf areaEnergyMolecularParametersOxidationPathwaysOccursP700ChloroplastStoichiometriesCarbonPulseCompoundsCatalysesPhotolysisDark ReactionActivityWaterImportantSystem
Photosynthesis22
- Light reaction of photosynthesis is one of the most important reactions for sustaining our environment. (elifesciences.org)
- This study adds a valuable new perspective to a long-standing question: What controls the repair of photosystem II (PSII), a key process in maintaining and optimizing photosynthesis? (elifesciences.org)
- The Cyanobacteria are inferred to be ancestrally nonphototrophic and acquired the ability for photosynthesis (PSI and PSII) after the divergence of the Oxyphotobacteria from the Melainabacteria. (dhushara.com)
- Which one of the following is not true about the light reactions of photosynthesis? (saranextgen.com)
- The thylakoid membrane is the site of the light reactions of photosynthesis. (flashcardmachine.com)
- Our findings suggest the importance of the buildup of ΔpH depending on CF0 CF1 -ATP synthase to adjust the redox state of the reaction center chlorophyll P700 in PSI and to suppress the production of ROS in PSI during photosynthesis. (bvsalud.org)
- PCC 6803 (S. 6803(WT)), the quantum yield of PSII, Y(II), held even after photosynthesis was suppressed by CO2 shortage. (bvsalud.org)
- The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy. (goldenssport.com)
- Select the most accurate statement describing the basic function of the light reactions of photosynthesis. (goldenssport.com)
- Light reactions take place during the first stage of photosynthesis. (nextgurukul.in)
- However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. (silverchair.com)
- The first bacteria carried out only anoxygenic photosynthesis catalyzed by one type of reaction center, type I or II, which somehow came together in cyanobacteria, and evolved into photosystems I and II. (rug.nl)
- Photosystem II (PSII) is a light-driven protein, involved in the primary reactions of photosynthesis. (hal.science)
- Voiceover] We've seen in previous videos that photosynthesis can be broken down into the light-dependent reactions and the Calvin cycle. (sciencespo-lille.com)
- The light reaction of photosynthesis initiates only when it is supplied with light energy. (sciencespo-lille.com)
- This is an online quiz called Light Dependent Reactions of Photosynthesis Quiz. (sciencespo-lille.com)
- the light-dependent reactions can occur only in the light, the light-independent reactions only in the dark: B) photorespiration is more efficient at producing glucose than is photosynthesis: C) the light-dependent reactions produce the energy-rich compounds that are used to run the light-independent reactions: D) all of the above are true following structures: (diagrams at right and below from Taiz & Zeiger). (sciencespo-lille.com)
- Photosynthesis is a redox reaction. (sciencespo-lille.com)
- Briefly describe the overall function of the light-dependent reactions in photosynthesis. (sciencespo-lille.com)
- The actinic light is a non-saturating, steady beam of light that allows photosynthesis to occur but does not saturate (close) all of the reaction centers. (weebly.com)
- In cyanobacteria and chloroplasts, in the presence of light, PSII functions as a water-plastoquinone oxidoreductase, transferring electrons from water to plastoquinone, whereas other photosynthetic bacteria carry out anoxygenic photosynthesis and oxidize other compounds to re-reduce the photoreaction center. (e-cyanobacterium.org)
- The first electron acceptor in the light-dependent reactions of photosynthesis. (e-cyanobacterium.org)
Photosystems3
- Cyanobacteria, the precursor to chloroplasts found in green plants, have both photosystems with both types of reaction centers. (goldenssport.com)
- a. the matrix d. photosystems I and II b. carbon In PSII, energy from sunlight is used to split water, which releases two electrons, two hydrogen atoms, and one oxygen atom. (sciencespo-lille.com)
- Simultaneous measurements of chlorophyll fluorescence and absorption changes at 820 nm indicated that differences between plants grown under alternative light regimes can be ascribed to imbalances in excitation of photosystems I and II (PSI, PSII). (ckbiobank.org)
Photosystem II11
- It specifically plays an inhibitory role in photosystem II (PSII) by blocking the flow of electrons from QA to QB. (wikipedia.org)
- Photosystem II (PSII) is the initial site of photosynthetic electron transfer by water oxidation. (elifesciences.org)
- In photosynthetic organisms, maintenance of photosynthetic light reaction is manifested by so called Photosystem II (PSII) repair system, where the reaction center protein D1 is targeted to photo-oxidative damage and rapidly degraded by the processive protease FtsH. (elifesciences.org)
- The first step of photosynthetic electron transfer in the thylakoid membrane occurs at Photosystem II (PSII), where light energy absorbed by P 680 chlorophyll molecules drives water oxidation, and electron is transferred to plastoquinone. (elifesciences.org)
- The instrument uses an array of software-controlled excitation light sources operating in pulse/DC mode to manipulate the state of photosynthetic reaction centers while measuring changes in the fluorescence signal emanating from Photosystem II chlorophyll antenna. (soliense.com)
- The difference between Photosystem II and the bacterial reaction center is the source of the electron that neutralizes the pair of chlorophyll a molecules. (goldenssport.com)
- The structure of Photosystem II is remarkably similar to the bacterial reaction center, and it is theorized that they share a common ancestor. (goldenssport.com)
- We employed digital RGB imaging to study shoot growth, and chlorophyll (Chl) fluorescence imaging (CFIM) to analyze various parameters of plant photosystem II (PSII) efficiency. (biomedcentral.com)
- The light-dependent reactions begin in photosystem II. (sciencespo-lille.com)
- At 27/22 ◦ C (day/night), drought stress led to the oxidation of the reaction center of the chlorophyll of PSI (P700), and also led to decreases in the quantum efficiencies of photosystem II (PSII) and PSI, and a reduction of the primary quinone electron acceptor of PSI. (elsevierpure.com)
- The reaction center chlorophyll (or the primary electron donor) of photosystem II that is most reactive and best in absorbing light at wavelength of 680 nm. (e-cyanobacterium.org)
Complexes4
- The cytochrome b6f complex occupies a central position in the sequence of photosynthetic electron transport carriers, oxidizing plastoquinol (PQH 2) and providing the electron transfer connection between the two reaction center complexes, PS II and PS I, to which H + transfer is coupled, thus contributing to the trans-membrane. (rehabsociety.org.hk)
- In plant photosynthetic membranes PSII forms large multisubunit supercomplexes, containing a dimeric core and up to four light-harvesting complexes (LHCs), which act as antenna proteins. (hal.science)
- Unlike reaction centers, LH complexes exhibit a large variability among photosynthetic organisms. (polivkalab.cz)
- A membrane enriched in complexes formed of reaction centers, accessory pigments and electron carriers, in which photosynthetic reactions take place. (e-cyanobacterium.org)
P6801
- PSII donor side P680 + quenching (1) . (soliense.com)
Fluorescence3
- The amount of fluorescence detected in the dark is the background level when all reaction centers are open and is designated F 0 or minimal fluorescence. (weebly.com)
- The top of the peak, when all of the reaction centers are closed, is labeled F m or maximal fluorescence. (weebly.com)
- Measurements of chlorophyll fluorescence emission and excitation spectra at 77 K provided strong evidence that there was little or no difference in the composition or function of PSI or PSII between the two sets of plants, implying that changes in photosynthetic stoichiometry are primarily responsible for the observed differences in photosynthetic function. (ckbiobank.org)
Protein6
- To maintain photosynthetic activity, the PSII reaction center protein D1, which is the primary target of unavoidable photo-oxidative damage, is efficiently degraded by FtsH protease. (elifesciences.org)
- Further characterization of Trp-14 using chloroplast transformation in Chlamydomonas indicated that substitution of D1 Trp-14 to Phe, mimicking Trp oxidation enhanced FtsH-mediated D1 degradation under high light, although the substitution did not affect protein stability and PSII activity. (elifesciences.org)
- The work supports a role for chemical modification in the recognition and subsequent degradation of a key protein subunit of PSII by a bacterial-type protease, suggesting that tryptophan oxidation of components of the photosynthetic apparatus after high light stress plays a critical role in initiating the PSII repair system. (elifesciences.org)
- In the bacterial reaction center, the electron is obtained from a reduced compound haem group in a cytochrome subunit or from a water-soluble cytochrome-c protein. (goldenssport.com)
- Additionally, the PSBS protein involved in NPQ and the minor PSII antenna protein LHCB4 were probed. (agrisera.com)
- the double reduced secondary quinone acceptor Qb2- is protonated plastoquinol and released from the Qb-binding pocket of the PSII D1 protein to plastoquinon pool. (e-cyanobacterium.org)
Acceptor2
- Light-induced signals originating from both donor and acceptor cofactors demonstrate that electron transfer occurs through both branches of cofactors in the pseudo- C 2 symmetric reaction center (RC). (copernicus.org)
- PSII acceptor side carotenoid quenching (1) . (soliense.com)
Efficiency1
- The efficiency of transfer of excitation energy from the chromophore that absorbed the photon to the reaction centre is very high (Collins et al. (harvard.edu)
Protons2
- The main function of PSII is to efficiently split water into oxygen molecules and protons. (goldenssport.com)
- Light reaction does not produce NADPH ATP Glucose protons 4. (sciencespo-lille.com)
Quinone1
- A photosystem that contains a pheophytin-quinone reaction center with associated accessory pigments and electron carriers. (e-cyanobacterium.org)
Flow of electrons1
- c. the flow of electrons from Which is formed during non-cyclic photophosphorylation but not during cyclic Where do the light-dependent reactions take place? (sciencespo-lille.com)
Electron trans1
- light dependent reaction electron transport chain calvin cycle photolysis. (sciencespo-lille.com)
Donor side3
- The decrease of PSII activity was mainly due to the reduction in the activity of oxygenevolving complex (OEC) on donor side of PSII and the blockage of electron transfer from Q A to Q B on receptor side of PSII. (cje.net.cn)
- The donor side of PSII was more sensitive to salt stress than the receptor side of PSII. (cje.net.cn)
- MT application can alleviate the damage on tomato caused by salt stress through balancing the electron transfer on donor side, receptor side and reaction center of PSII. (cje.net.cn)
Redox1
- First, the transfer of an electron from BPh− to P960+ is relatively slow compared to two other redox reactions in the reaction center. (goldenssport.com)
Absorption2
- Light reaction consists of the following four stages - light absorption, water splitting, release of oxygen and formation of high-energy intermediates ATP and NADPH. (nextgurukul.in)
- In the light-absorption stage, the chlorophyll a in PSII absorbs the 680 nm wavelength of red light. (nextgurukul.in)
Absorbs1
- The LH complex absorbs light energy and funnels it into the reaction center where the charge separation takes place. (polivkalab.cz)
Electrons from water1
- Both reaction center types are present in chloroplasts and cyanobacteria, and work together to form a unique photosynthetic chain able to extract electrons from water, creating high-energy oxygen as a byproduct. (goldenssport.com)
Antenna3
- PSII core complex is formed by two reaction center proteins D1 (PsbA) and D2 (PsbD), along with intrinsic antenna CP43 (PsbC) and CP47 (PsbB). (elifesciences.org)
- Photosynthetic apparatus of all photosynthetic organisms contains two vital components needed for the light reactions: a light-harvesting (LH) antenna and a reaction center. (polivkalab.cz)
- The decreased chlorophyll a / b ratio could be explained by the relative enrichment of light-harvesting antenna to reaction center with leaf senescence. (chinacrops.org)
Molecules1
- And finally, additional safeguard molecules 'deactivate' compounds that could otherwise mediate damaging reactions. (elifesciences.org)
LHCII1
- We located all 35 chlorophylls of the core region based on the cyanobacterial PSII structure, whose positioning is highly conserved, as well as all the chlorophylls of the LHCII S and M trimers. (hal.science)
Photon1
- 0.8 electrons per absorbed photon in PSII (Falkowski and Raven 2007 Johnsen and Sakshaug 2007 Hogewoning et al. (harvard.edu)
Chloroplasts1
- We found that the slug Elysia timida induces changes to the photosynthetic light reactions of the chloroplasts it steals from the alga Acetabularia acetabulum . (elifesciences.org)
Reduction1
- The reaction, Fe 3+ → Fe 2+ is an example of: a. oxidation b. reduction. (sciencespo-lille.com)
Vivo1
- Furthermore, Trp-14 to Phe modification appeared to have an additive effect in the interaction between FtsH and PSII core in vivo. (elifesciences.org)
Complex2
- In the 1960s, Roderick Clayton was the first to purify the reaction center complex from purple bacteria. (goldenssport.com)
- In the center of the oxygen evolving complex (OEC) was attacked by studies by Yachandra and coworkers (17-19), it was concluded a manganese-bridging oxo group. (lu.se)
Excitation1
- In addition, the ability of PSII reaction center to harvest and utilize light energy, the concentration of reaction centers (expressed as per unit leaf area) and the ratio of excitation energy to absorbed energy were all decreased. (cje.net.cn)
Leaf area1
- The content of PS II reaction centres was unchanged on a leaf area basis, but there was evidence for increases in the relative levels of other light harvesting proteins, notably CP26, associated with PS II, and Lhca4, associated with PS I. Electron microscopy showed the presence of grana. (ox.ac.uk)
Energy5
- Probability of energy transfer between PSII reaction centers. (soliense.com)
- The bacterial photosynthetic reaction center has been an important model to understand the structure and chemistry of the biological process of capturing light energy. (goldenssport.com)
- PSII will provide a steady stream of electrons to PSI, which will boost these in energy and transfer them to NADP+ and H+ to make NADPH. (goldenssport.com)
- The cyclic pathway of light-dependent reactions uses ____ to absorb light energy and emit electrons. (sciencespo-lille.com)
- It is of interest how photosynthetic electron transport (PET) reactions respond to excess light energy caused by the combination of drought stress and high temperatures. (elsevierpure.com)
Molecular2
- Molecular dynamics simulation of PSII implies that both Trp-14 oxidation and Phe substitution cause fluctuation of D1 N-terminal tail. (elifesciences.org)
- He was Head of the Department of Molecular Biology and Pharmacology from 1991-2004 before becoming the founding Director of a University-wide, Center for Genome Sciences and Systems Biology. (amphilsoc.org)
Parameters1
- FIRe parameters were set to measure single turnover flash of PSII reaction centers (single closure event) with a sample delay of 100, and a total of 50 samples (Gorbunov and Falkowski 2004). (bco-dmo.org)
Oxidation2
- Together, our results suggest that the Trp oxidation at its N-terminus of D1 may be one of the key oxidations in the PSII repair, leading to processive degradation by FtsH. (elifesciences.org)
- Here, we characterized oxidative modification of tryptophan (Trp) residues in the PSII core, and hypothesize that the oxidation of N-terminal Trp is one of the key oxidations in the PSII repair, likely enhancing D1's accessibility to FtsH. (elifesciences.org)
Pathways1
- In those pathways, FNR however catalyses the opposite reaction, namely the production of reduced Fd 4 and is thus sometimes classified as heterotrophic FNR. (nature.com)
Occurs1
- Photoinhibition occurs when the reaction centers start becoming damaged and must be broken down to be repaired. (weebly.com)
P7001
- These results indicate that the drought stress responses of the respective PET reactions are closely associated with each other in the oxidization of P700 and that such responses are stimulated at high temperatures. (elsevierpure.com)
Chloroplast1
- Where in the chloroplast do the 'light' or light-dependent reactions occur? (sciencespo-lille.com)
Stoichiometries1
- Landsberg erecta was grown under light regimes of differing spectral qualities, which results in differences in the stoichiometries of the two photosynthetic reaction centres. (ckbiobank.org)
Carbon1
- For example, overwintering evergreens have developed so-called sustained non-photochemical quenching (reviewed, e.g., by Verhoeven [ 4 ]) as a protection mechanism against absorbed light which is in excess with respect to the capacity of the carbon photosynthetic reactions and which is decreased during winter. (biomedcentral.com)
Pulse1
- This saturating pulse is a very strong light, providing a plethora of photons and rendering all of the reaction centers closed. (weebly.com)
Compounds1
- The review is summarized and systematized the published data on the multicomponent reactions of ethyl trifluoroacetoacetate, carbonyl compounds (aldehydes and ketones), and nucleophilic reagents. (researchgate.net)
Catalyses1
- Powered by light, this enzyme catalyses the chemically and thermodynamically demanding reaction of water splitting. (goldenssport.com)
Photolysis1
- This quiz/worksheet combo will help you review photolysis and the overarching concept of light reactions. (sciencespo-lille.com)
Dark Reaction1
- Treatment with 96 kJ·m −2 ·d −1 enhanced ultraviolet-B radiation improved Rubisco activity by increasing the expression of the Rubisco large and small subunit genes, thereby enhancing the CO 2 -fixing capacity and dark reaction capacity of leaves. (ashs.org)
Activity1
- The net photosynthetic rate (P n ), photosynthetic pigment content, Hill reaction activity, and photochemical quenching coefficient (qP) of the treated leaves showed significantly higher values than those of the control leaves. (ashs.org)
Water3
- 55 It was found that the solventfree reaction of ETFAA 1a, benzaldehyde, and ammonium acetate at 100 C proceeded with the loss of the water molecule to aff ord partially dehydrated 2-hydroxy-2,6-bis(trifl uoromethyl)-1,2,3,4-tetrahydropyridine-3,5-dicarboxylate 6. (researchgate.net)
- This process, known as Mehler reaction, results in formation of H 2 O 2 which is generated by the superoxide dismutase (SOD) and converted into water and oxygen by ascorbate peroxidase 9 . (nature.com)
- Mehler reaction, or water-water cycle, allows functionality of the CET and subsequent synthesis of ATP needed for the Calvin cycle, which finally oxidizes NADPH to re-establish LET 5 . (nature.com)
Important1
- The state of the reaction centers are important. (weebly.com)
System1
- constitutes the reaction centre of photo system-II. (saranextgen.com)