943:
20:
345:. The electron can be transferred to another molecule. As the ionized pigment returns to the ground state, it takes up an electron and gives off energy to the oxygen evolving complex so it can split water into electrons, protons, and molecular oxygen (after receiving energy from the pigment four times). Plant pigments usually utilize the last two of these reactions to convert the sun's energy into their own.
252:
324:
energy cannot be absorbed and is reflected. 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 (
827:) molecule by ripping off one of its hydrogen atoms. The high-energy oxidized tyrosine gives off its energy and returns to the ground state by taking up a proton and removing an electron from the oxygen-evolving complex and ultimately from water. Kok's S-state diagram shows the reactions of water splitting in the oxygen-evolving complex.
1371:), and then returned to the chlorophyll molecule. The result is a proton gradient that is used to make ATP via ATP synthase. As in cyanobacteria and chloroplasts, this is a solid-state process that depends on the precise orientation of various functional groups within a complex transmembrane macromolecular structure.
1436:, electrons are removed from an excited chlorophyll molecule, passed through an electron transport chain to a proton pump, and then returned to the chlorophyll. The mobile electron carriers are, as usual, a lipid-soluble quinone and a water-soluble cytochrome. The resulting proton gradient is used to make ATP.
356:
on the acceptor could move back to neutralize the positive charge on the special pair. Its return to the special pair would waste a valuable high-energy electron and simply convert the absorbed light energy into heat. In the case of PSII, this backflow of electrons can produce reactive oxygen species
336:
of the special pair in the reaction center becomes excited, it cannot transfer this energy to another pigment using resonance energy transfer. Under normal circumstances, the electron would return to the ground state, but because the reaction center is arranged so that a suitable electron acceptor is
778:
of the reaction center pigment P680 occurs here. These special chlorophyll molecules embedded in PSII absorb the energy of photons, with maximal absorption at 680 nm. Electrons within these molecules are promoted to a higher-energy state. This is one of two core processes in photosynthesis, and
839:
The emergence of such an incredibly complex structure, a macromolecule that converts the energy of sunlight into chemical energy and thus potentially useful work with efficiencies that are impossible in ordinary experience, seems almost magical at first glance. Thus, it is of considerable interest
951:
f, to another transport protein, plastocyanin (Pc), and back to photosystem I. A proton gradient is created across the thylakoid membrane (6) as protons (3) are transported from the chloroplast stroma (4) to the thylakoid lumen (5). Through chemiosmosis, ATP (9) is produced where ATP synthase (1)
323:
Electrons in pigment molecules can exist at specific energy levels. Under normal circumstances, they are at the lowest possible energy level, the ground state. However, absorption of light of the right photon energy can lift them to a higher energy level. Any light that has too little or too much
1125:
Unlike plants and algae, cyanobacteria are prokaryotes. They do not contain chloroplasts; rather, they bear a striking resemblance to chloroplasts themselves. This suggests that organisms resembling cyanobacteria were the evolutionary precursors of chloroplasts. One imagines primitive eukaryotic
1027:
The light-harvesting system of PSI uses multiple copies of the same transmembrane proteins used by PSII. The energy of absorbed light (in the form of delocalized, high-energy electrons) is funneled into the reaction center, where it excites special chlorophyll molecules (P700, with maximum light
311:
pigment molecules near the periplasmic (or thylakoid lumen) side of the membrane. This dimer is called a special pair because of its fundamental role in photosynthesis. This special pair is slightly different in PSI and PSII reaction centers. In PSII, it absorbs photons with a wavelength of
794:, which occurs within the reaction center of PSII. The electrons are transferred to plastoquinone and two protons, generating plastoquinol, which released into the membrane as a mobile electron carrier. This is the second core process in photosynthesis. The initial stages occur within
914:
in mitochondria). Both are transmembrane structures that remove electrons from a mobile, lipid-soluble electron carrier (plastoquinone in chloroplasts; ubiquinone in mitochondria) and transfer them to a mobile, water-soluble electron carrier (plastocyanin in chloroplasts; cytochrome
802:
process, not a typical chemical reaction. It occurs within an essentially crystalline environment created by the macromolecular structure of PSII. The usual rules of chemistry (which involve random collisions and random energy distributions) do not apply in solid-state environments.
835:
PSII is a transmembrane structure found in all chloroplasts. It splits water into electrons, protons and molecular oxygen. The electrons are transferred to plastoquinol, which carries them to a proton pump. The oxygen is released into the atmosphere.
1522:, showing the light and dark reactions occurred in different places. Although they are referred to as light and dark reactions, both of them take place only in the presence of light. This led later to the discovery of photosystems I and II.
892:. This redox process is coupled to the pumping of four protons across the membrane. The resulting proton gradient (together with the proton gradient produced by the water-splitting complex in PSI) is used to make ATP via ATP synthase.
946:
The cyclic light-dependent reactions occur only when the sole photosystem being used is photosystem I. Photosystem I excites electrons which then cycle from the transport protein, ferredoxin (Fd), to the cytochrome complex,
1117:
are found in chloroplasts. All plants and all photosynthetic algae contain chloroplasts, which produce NADPH and ATP by the mechanisms described above. In essence, the same transmembrane structures are also found in
1315:
Cyanobacteria are the only bacteria that produce oxygen during photosynthesis. Earth's primordial atmosphere was anoxic. Organisms like cyanobacteria produced our present-day oxygen-containing atmosphere.
466:
molecules. PSI can continue the electron transfer in two different ways. It can transfer the electrons either to plastoquinol again, creating a cyclic electron flow, or to an enzyme called FNR (
121:
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
1443:, electrons are removed from an excited chlorophyll molecule and used to reduce NAD to NADH. The electrons removed from P840 must be replaced. This is accomplished by removing electrons from
563:(P680), pheophytin (a pigment similar to chlorophyll), and two quinones. It uses the energy of sunlight to transfer electrons from water to a mobile electron carrier in the membrane called
1706:"Sequence homology and structural similarity between cytochrome b of mitochondrial complex III and the chloroplast b6-f complex: position of the cytochrome b hemes in the membrane"
964:
1494:
proposed in 1931 that photosynthesis is a case of general mechanism where a photon of light is used to photo decompose a hydrogen donor and the hydrogen being used to reduce
375:
The electron transfer back from the electron acceptor to the positively charged special pair is especially slow. The rate of an electron transfer reaction increases with its
113:. The resulting proton gradient across the thylakoid membrane creates a proton-motive force, used by ATP synthase to form ATP. In cyclic photophosphorylation, cytochrome
978:
1020:
PSI, like PSII, is a complex, highly organized transmembrane structure that contains antenna chlorophylls, a reaction center (P700), phylloquinone, and a number of
779:
it occurs with astonishing efficiency (greater than 90%) because, in addition to direct excitation by light at 680 nm, the energy of light first harvested by
1319:
The other two major groups of photosynthetic bacteria, purple bacteria and green sulfur bacteria, contain only a single photosystem and do not produce oxygen.
387:
Thus, electron transfer proceeds efficiently from the first electron acceptor to the next, creating an electron transport chain that ends when it has reached
320:. In bacteria, the special pair is called P760, P840, P870, or P960. "P" here means pigment, and the number following it is the wavelength of light absorbed.
798:, with an efficiency of 100%. The seemingly impossible efficiency is due to the precise positioning of molecules within the reaction center. This is a
439:, an electron is again excited, creating a high redox-potential. The electron transport chain of photosynthesis is often put in a diagram called the
341:
process, further boosts its energy. The formation of a positive charge on the special pair and a negative charge on the acceptor is referred to as
762:
The electrons are transferred to special chlorophyll molecules (embedded in PSII) that are promoted to a higher-energy state by the energy of
372:
An electron donor is less than 1 nm away from the special pair, and so the positive charge is neutralized by the transfer of another electron.
1765:"Biological identity and diversity in photosynthesis and respiration: structure of the lumen-side domain of the chloroplast Rieske protein"
61:
and then to PSI. The then-reduced PSI, absorbs another photon producing a more highly reducing electron, which converts NADP to NADPH. In
337:
nearby, the excited electron is taken up by the acceptor. The loss of the electron gives the special pair a positive charge and, as an
1230:
Cyanobacteria can also synthesize ATP by oxidative phosphorylation, in the manner of other bacteria. The electron transport chain is
886:, where they are removed in a stepwise fashion (re-forming plastoquinone) and transferred to a water-soluble electron carrier called
688:
using energy from P680. The actual steps of the above reaction possibly occur in the following way (Kok's diagram of S-states): (I) 2
369:
is less than 1 nanometer away from the first acceptor, and so the electron is rapidly transferred farther away from the special pair.
1220:
is, in essence, the same as the electron transport chain in chloroplasts. The mobile water-soluble electron carrier is cytochrome
1378:, sulfur, sulfite, or organic molecules such as succinate and lactate) to feed electrons into a reverse electron transport chain.
1094:. The ratio of NADPH to ATP production can be adjusted by adjusting the balance between cyclic and noncyclic electron transport.
352:(10 seconds). In their high-energy states, the special pigment and the acceptor could undergo charge recombination; that is, the
1851:
is the main respiratory and photosynthetic soluble electron donor in heterocysts of the cyanobacterium
Anabaena sp. PCC 7120"
1470:
occupy relatively minor ecological niches in the present day biosphere. They are of interest because of their importance in
1474:
ecologies, and because their methods of photosynthesis were the likely evolutionary precursors of those in modern plants.
361:. Three factors in the structure of the reaction center work together to suppress charge recombination nearly completely:
1610:"Mechanism of photosystem II photoinactivation and D1 protein degradation at low light: the role of back electron flow"
1031:
Electrons are removed from excited chlorophyll molecules and transferred through a series of intermediate carriers to
1045:
467:
1309:
1037:, a water-soluble electron carrier. As in PSII, this is a solid-state process that operates with 100% efficiency.
1082:. They are then returned (via plastocyanin) to P700. NADPH and ATP are used to synthesize organic molecules from
783:
at other wavelengths in the light-harvesting system is also transferred to these special chlorophyll molecules.
38:, the main process by which plants acquire energy. There are two light dependent reactions: the first occurs at
1536:
454:, a mobile electron carrier in the membrane. Plastoquinol transfers the electron from PSII to the proton pump,
342:
298:
197:
1806:"Crystal structure of chloroplast cytochrome f reveals a novel cytochrome fold and unexpected heme ligation"
1028:
absorption at 700 nm) to a higher energy level. The process occurs with astonishingly high efficiency.
919:
in mitochondria). Both are proton pumps that produce a transmembrane proton gradient. In fact, cytochrome b
1141:
contain both PSI and PSII. Their light-harvesting system is different from that found in plants (they use
122:
234:. This article discusses a specific subset of these, the series of light-dependent reactions related to
1531:
1330:
contain a single photosystem that is structurally related to PSII in cyanobacteria and chloroplasts:
329:
1960:
van Niel, C. B. (1931). "On the morphology and physiology of the purple and green sulfur bacteria".
2044:
927:
and the Rieske iron-sulfur proteins of the two complexes are homologous. However, cytochrome f and
872:
432:
269:
177:
50:
504:
from the stroma to the lumen. The resulting transmembrane proton gradient is used to make ATP via
218:, many reactions depend on the absorption of photons to provide the energy needed to overcome the
2049:
1507:
638:
328:). The energy, but not the electron itself, may be passed onto another molecule; this is called
860:
379:
up to a point and then decreases. The back transfer is so favorable that it takes place in the
31:
1845:
Torrado, A; Ramírez-Moncayo, C; Navarro, JA; Mariscal, V; Molina-Heredia, FP (January 2019).
1467:
1386:
1098:
262:
1909:
1074:, electrons from ferredoxin are transferred (via plastoquinol) to a proton pump, cytochrome
2004:
1717:
1621:
90:
303:
The reaction center is in the thylakoid membrane. It transfers absorbed light energy to a
8:
1021:
799:
49:
PSII absorbs a photon to produce a so-called high energy electron which transfers via an
2008:
1721:
1625:
440:
78:
62:
2020:
1977:
1942:
1890:
1546:
511:
The overall process of the photosynthetic electron transport chain in chloroplasts is:
376:
1822:
1805:
1781:
1764:
1740:
1705:
550:
PSII is extremely complex, a highly organized transmembrane structure that contains a
1946:
1882:
1827:
1786:
1745:
1649:
1644:
1609:
1590:
1491:
1486:
in 1779 who recognized it was sunlight falling on plants that was required, although
1147:, rather than chlorophylls, as antenna pigments), but their electron transport chain
424:
366:
304:
219:
200:, is the start of the electron flow and transforms light energy into chemical forms.
2024:
1981:
1894:
632:
is performed by an imperfectly understood structure embedded within PSII called the
2012:
1969:
1934:
1872:
1862:
1817:
1776:
1735:
1725:
1668:
1639:
1629:
1582:
1487:
1375:
942:
1586:
1867:
1846:
1463:
1360:; P870), passed through an electron transport chain to a proton pump (cytochrome
1327:
841:
646:). It catalyzes a reaction that splits water into electrons, protons and oxygen,
559:
552:
358:
277:
222:
barrier and hence can be labelled light-dependent. Such reactions range from the
181:
128:
The net-reaction of all light-dependent reactions in oxygenic photosynthesis is:
110:
1710:
Proceedings of the
National Academy of Sciences of the United States of America
1614:
Proceedings of the
National Academy of Sciences of the United States of America
1541:
1490:
had noted the production of oxygen without the association with light in 1772.
1483:
1126:
cells taking up cyanobacteria as intracellular symbionts in a process known as
1097:
It is noteworthy that PSI closely resembles photosynthetic structures found in
545:
471:
455:
400:
273:
235:
209:
106:
39:
35:
2038:
1356:
process in which electrons are removed from an excited chlorophyll molecule (
1138:
1127:
957:
928:
806:
565:
420:
380:
223:
189:
43:
962:
PSI accepts electrons from plastocyanin and transfers them either to NADPH (
2016:
1938:
1886:
1653:
1634:
1594:
924:
888:
505:
463:
451:
404:
325:
1831:
1804:
Martinez SE, Huang D, Szczepaniak A, Cramer WA, Smith JL (February 1994).
1790:
1749:
1730:
1482:
The first ideas about light being used in photosynthesis were proposed by
1997:
Proceedings of the Royal
Society of London. Series B, Biological Sciences
1471:
1374:
To make NADPH, purple bacteria use an external electron donor (hydrogen,
875:
308:
231:
1877:
1204:↑ ↓
1973:
1510:
demonstrated that isolated chloroplasts would make oxygen, but not fix
1143:
1033:
492:
Activities of the electron transport chain, especially from cytochrome
349:
338:
226:
reactions used in photographic film to the creation and destruction of
93:) in two distinct ways. In non-cyclic photophosphorylation, cytochrome
19:
1844:
1571:"Janus-faced charge recombinations in photosystem II photoinhibition"
215:
23:
Light-dependent reactions of photosynthesis at the thylakoid membrane
1570:
1286:
where the mobile electron carriers are plastoquinol and cytochrome
408:
353:
333:
193:
185:
1227:
in cyanobacteria, having been replaced by plastocyanin in plants.
1040:
There are two different pathways of electron transport in PSI. In
470:), creating a non-cyclic electron flow. PSI releases FNR into the
1995:
Hill, R. (May 1939). "Oxygen
Produced by Isolated Chloroplasts".
763:
102:
1389:
contain a photosystem that is analogous to PSI in chloroplasts:
1925:
Priestley, J (1772). "Observations on
Different Kinds of Air".
815:
passes the electron to pheophytin, it converts to high-energy P
501:
70:
1803:
1101:, just as PSII resembles structures found in purple bacteria.
952:
binds an inorganic phosphate group (8) to an ADP molecule (7).
1704:
Widger WR, Cramer WA, Herrmann RG, Trebst A (February 1984).
486:
444:
428:
388:
227:
66:
458:. The ultimate electron donor of PSII is water. Cytochrome b
431:
potentials. This chain of electron acceptors is known as an
859:
PSII and PSI are connected by a transmembrane proton pump,
436:
416:
412:
317:
313:
1763:
Carrell CJ, Zhang H, Cramer WA, Smith JL (December 1997).
1703:
878:). Electrons from PSII are carried by plastoquinol to cyt
807:
Link of water-splitting complex and chlorophyll excitation
316:. In PSI, it absorbs photons at 700 nm and is called
1927:
1762:
348:
This initial charge separation occurs in less than 10
1456:, which is oxidized to sulfur (hence the name "green
1293:, while the proton pumps are NADH dehydrogenase, cyt
101:
uses electrons from PSII and energy from PSI to pump
1608:
Keren N, Berg A, Levanon H, Ohad I (February 1997).
1607:
180:. If a special pigment molecule in a photosynthetic
1855:
Biochimica et
Biophysica Acta (BBA) - Bioenergetics
1691:McGraw Hill Encyclopedia of Science and Technology
600:Plastoquinol, in turn, transfers electrons to cyt
447:diagram from P680 to P700 resembles the letter Z.
840:that, in essence, the same structure is found in
2036:
1432:There are two pathways of electron transfer. In
1044:, ferredoxin carries the electron to the enzyme
903:(in chloroplasts) is very similar to cytochrome
423:level. This energy is used to reduce a chain of
923:and subunit IV are homologous to mitochondrial
89:and ATP synthase work together to produce ATP (
81:, various electron donors are used. Cytochrome
1407:↑ ↓
1004:↑ ↓
759:(di-oxygen). (Dolai's mechanism)
462:f transfers the electron chain to PSI through
196:in the reaction center. This reaction, called
1797:
383:where electron-transfer rates become slower.
203:
1756:
1666:
1024:that serve as intermediate redox carriers.
1907:
1697:
1564:
1562:
786:This is followed by the electron transfer
611:
557:, chlorophylls and carotenoid pigments, a
1924:
1876:
1866:
1821:
1780:
1739:
1729:
1643:
1633:
895:The structure and function of cytochrome
1959:
1669:"The Z-Scheme Diagram of Photosynthesis"
1601:
1568:
1381:
941:
18:
1559:
2037:
871:(plastoquinol—plastocyanin reductase;
312:680 nm, and is therefore called
1994:
769:
245:
1368:
192:and then is transferred to another
13:
1322:
394:
241:
14:
2061:
847:
539:
1133:
937:
819:, which can oxidize the tyrosine
250:
1988:
1953:
1918:
1334:P870 → P870 → ubiquinone → cyt
1901:
1838:
1682:
1660:
1537:Photosynthetic reaction centre
1104:
811:When the excited chlorophyll P
427:that have subsequently higher
343:photoinduced charge separation
299:Photosynthetic reaction center
198:photoinduced charge separation
65:, the first electron donor is
1:
1823:10.1016/s0969-2126(00)00012-5
1782:10.1016/s0969-2126(97)00309-2
1587:10.1016/j.tplants.2009.01.009
1569:Vass I, Cser K (April 2009).
1552:
608:, which feeds them into PSI.
450:The final product of PSII is
276:in tone and meet Knowledge's
1868:10.1016/j.bbabio.2018.11.009
1042:noncyclic electron transport
965:noncyclic electron transport
535:→ plastocyanin → PSI → NADPH
527:→ PSII → plastoquinol → cyt
468:Ferredoxin—NADP(+) reductase
188:in this pigment attains the
7:
1914:. London: Elmsly and Payne.
1911:Experiments Upon Vegetables
1525:
1441:noncyclic electron transfer
123:light-independent reactions
10:
2066:
1532:Light-independent reaction
1477:
1109:PSII, PSI, and cytochrome
955:
830:
543:
435:. When this chain reaches
377:thermodynamic favorability
296:
207:
178:light-harvesting complexes
1072:cyclic electron transport
979:cyclic electron transport
330:resonance energy transfer
204:Light dependent reactions
79:anoxygenic photosynthesis
42:and the second occurs at
28:Light-dependent reactions
1434:cyclic electron transfer
968:) or back to cytochrome
433:electron transport chain
51:electron transport chain
16:Photosynthetic reactions
1575:Trends in Plant Science
639:oxygen-evolving complex
634:water-splitting complex
612:Water-splitting complex
63:oxygenic photosynthesis
32:photochemical reactions
2017:10.1098/rspb.1939.0017
1939:10.1098/rstl.1772.0021
1908:Ingenhousz, J (1779).
1635:10.1073/pnas.94.4.1579
953:
77:) as a by-product. In
24:
1731:10.1073/pnas.81.3.674
1468:green sulfur bacteria
1387:Green sulfur bacteria
1382:Green sulfur bacteria
1369:the chloroplastic one
1099:green sulfur bacteria
945:
500:, lead to pumping of
238:in living organisms.
184:absorbs a photon, an
172:+ 2 H + 2NADPH + 3ATP
40:photosystem II (PSII)
22:
1693:. 2007. p. 472.
1367:complex; similar to
1022:iron-sulfur proteins
934:are not homologous.
701:(monoxide) (II) OH.
270:improve this article
91:photophosphorylation
2009:1939RSPSB.127..192H
1722:1984PNAS...81..674W
1626:1997PNAS...94.1579K
1358:bacteriochlorophyll
1059:(FNR) that reduces
474:, where it reduces
44:photosystem I (PSI)
1974:10.1007/BF00454965
1689:"Photosynthesis".
1547:Compensation point
1234:NADH dehydrogenase
954:
714:(hydroxide) (III)
425:electron acceptors
25:
1667:Rajni Govindjee.
1492:Cornelis Van Niel
790:, and then on to
788:P680 → pheophytin
747:(super oxide)(V)
367:electron acceptor
295:
294:
278:quality standards
220:activation energy
176:PSI and PSII are
2057:
2029:
2028:
2003:(847): 192–210.
1992:
1986:
1985:
1957:
1951:
1950:
1922:
1916:
1915:
1905:
1899:
1898:
1880:
1870:
1842:
1836:
1835:
1825:
1801:
1795:
1794:
1784:
1760:
1754:
1753:
1743:
1733:
1701:
1695:
1694:
1686:
1680:
1679:
1677:
1675:
1664:
1658:
1657:
1647:
1637:
1605:
1599:
1598:
1566:
1521:
1520:
1519:
1506:. Then in 1939,
1505:
1504:
1503:
1488:Joseph Priestley
1455:
1453:
1452:
1376:hydrogen sulfide
1282:
1281:
1280:
1162:
1160:
1159:
1093:
1092:
1091:
1069:
1068:
1067:
1056:
1055:
1054:
781:antenna proteins
758:
757:
756:
746:
745:
744:
734:
733:
732:
724:
723:
713:
711:
710:
700:
698:
697:
684:
683:
682:
662:
660:
659:
629:
627:
626:
584:
582:
581:
526:
524:
523:
484:
483:
482:
290:
287:
281:
254:
253:
246:
232:upper atmosphere
171:
170:
169:
155:
154:
153:
144:
142:
141:
2065:
2064:
2060:
2059:
2058:
2056:
2055:
2054:
2045:Light reactions
2035:
2034:
2033:
2032:
1993:
1989:
1962:Arch. Microbiol
1958:
1954:
1923:
1919:
1906:
1902:
1850:
1843:
1839:
1802:
1798:
1775:(12): 1613–25.
1761:
1757:
1702:
1698:
1688:
1687:
1683:
1673:
1671:
1665:
1661:
1606:
1602:
1567:
1560:
1555:
1528:
1518:
1515:
1514:
1513:
1511:
1502:
1499:
1498:
1497:
1495:
1480:
1464:Purple bacteria
1451:
1448:
1447:
1446:
1444:
1430:
1423:
1414:
1384:
1365:
1346:
1339:
1328:Purple bacteria
1325:
1323:Purple bacteria
1308:(member of the
1306:
1301:and cytochrome
1298:
1291:
1284:
1279:
1276:
1275:
1274:
1272:
1267:
1257:
1246:
1225:
1218:
1210:
1189:
1178:
1158:
1155:
1154:
1153:
1151:
1136:
1114:
1107:
1090:
1087:
1086:
1085:
1083:
1079:
1066:
1064:
1063:
1062:
1060:
1053:
1051:
1050:
1049:
1047:
1018:
1010:
973:
960:
950:
940:
932:
922:
908:
900:
883:
866:
857:
853:
842:purple bacteria
833:
826:
822:
818:
814:
809:
774:The excitation
772:
770:Reaction center
755:
752:
751:
750:
748:
743:
740:
739:
738:
736:
735:(peroxide) (IV)
731:
728:
727:
726:
722:
719:
718:
717:
715:
709:
706:
705:
704:
702:
696:
693:
692:
691:
689:
686:
681:
678:
677:
676:
674:
658:
655:
654:
653:
651:
625:
622:
621:
620:
618:
614:
605:
598:
580:
577:
576:
575:
573:
560:reaction center
553:water splitting
548:
542:
537:
532:
522:
519:
518:
517:
515:
497:
481:
479:
478:
477:
475:
461:
407:begins when an
397:
395:In chloroplasts
381:inverted region
359:photoinhibition
301:
291:
285:
282:
267:
255:
251:
244:
242:Reaction center
212:
206:
182:reaction center
168:
165:
164:
163:
161:
159:
152:
150:
149:
148:
146:
140:
137:
136:
135:
133:
118:
98:
86:
76:
58:
17:
12:
11:
5:
2063:
2053:
2052:
2050:Photosynthesis
2047:
2031:
2030:
1987:
1952:
1917:
1900:
1848:
1837:
1796:
1755:
1696:
1681:
1659:
1620:(4): 1579–84.
1600:
1557:
1556:
1554:
1551:
1550:
1549:
1544:
1542:Photosystem II
1539:
1534:
1527:
1524:
1516:
1500:
1484:Jan IngenHousz
1479:
1476:
1449:
1421:
1412:
1391:
1383:
1380:
1363:
1350:
1349:
1344:
1337:
1324:
1321:
1304:
1296:
1289:
1277:
1265:
1255:
1244:
1232:
1223:
1208:
1187:
1176:
1156:
1149:
1135:
1132:
1112:
1106:
1103:
1088:
1077:
1065:
1052:
1008:
984:
971:
956:Main article:
948:
939:
936:
930:
920:
906:
898:
881:
864:
856:
851:
846:
832:
829:
824:
820:
816:
812:
808:
805:
771:
768:
753:
741:
729:
720:
707:
694:
679:
656:
648:
623:
613:
610:
603:
578:
571:
546:Photosystem II
544:Main article:
541:
540:Photosystem II
538:
530:
520:
513:
495:
480:
459:
456:cytochrome b6f
443:, because the
401:photosynthesis
396:
393:
385:
384:
373:
370:
297:Main article:
293:
292:
258:
256:
249:
243:
240:
236:photosynthesis
210:Photochemistry
208:Main article:
205:
202:
174:
173:
166:
157:
151:
138:
116:
96:
84:
74:
56:
53:to cytochrome
36:photosynthesis
15:
9:
6:
4:
3:
2:
2062:
2051:
2048:
2046:
2043:
2042:
2040:
2026:
2022:
2018:
2014:
2010:
2006:
2002:
1998:
1991:
1983:
1979:
1975:
1971:
1967:
1963:
1956:
1948:
1944:
1940:
1936:
1932:
1928:
1921:
1913:
1912:
1904:
1896:
1892:
1888:
1884:
1879:
1874:
1869:
1864:
1860:
1856:
1852:
1847:"Cytochrome c
1841:
1833:
1829:
1824:
1819:
1816:(2): 95–105.
1815:
1811:
1807:
1800:
1792:
1788:
1783:
1778:
1774:
1770:
1766:
1759:
1751:
1747:
1742:
1737:
1732:
1727:
1723:
1719:
1715:
1711:
1707:
1700:
1692:
1685:
1670:
1663:
1655:
1651:
1646:
1641:
1636:
1631:
1627:
1623:
1619:
1615:
1611:
1604:
1596:
1592:
1588:
1584:
1580:
1576:
1572:
1565:
1563:
1558:
1548:
1545:
1543:
1540:
1538:
1535:
1533:
1530:
1529:
1523:
1509:
1493:
1489:
1485:
1475:
1473:
1469:
1465:
1461:
1459:
1442:
1437:
1435:
1429:
1425:
1424:
1416:
1415:
1406:
1402:
1398:
1394:
1390:
1388:
1379:
1377:
1372:
1370:
1366:
1359:
1355:
1347:
1340:
1333:
1332:
1331:
1329:
1320:
1317:
1313:
1311:
1307:
1300:
1292:
1283:
1269:
1268:
1259:
1258:
1249:
1248:
1239:
1235:
1231:
1228:
1226:
1217:
1213:
1212:
1203:
1199:
1195:
1191:
1190:
1181:
1180:
1171:
1167:
1163:
1148:
1146:
1145:
1140:
1139:Cyanobacteria
1134:Cyanobacteria
1131:
1129:
1128:endosymbiosis
1123:
1121:
1120:cyanobacteria
1116:
1102:
1100:
1095:
1081:
1073:
1070:to NADPH. In
1058:
1043:
1038:
1036:
1035:
1029:
1025:
1023:
1017:
1016:phylloquinone
1013:
1012:
1003:
999:
995:
991:
987:
983:
981:
980:
975:
967:
966:
959:
958:Photosystem I
944:
938:Photosystem I
935:
933:
926:
918:
913:
909:
902:
893:
891:
890:
885:
877:
874:
870:
868:
855:
845:
843:
837:
828:
804:
801:
797:
793:
789:
784:
782:
777:
767:
765:
760:
685:
671:
667:
663:
647:
645:
641:
640:
635:
631:
609:
607:
597:
593:
589:
585:
570:
568:
567:
566:plastoquinone
562:
561:
556:
554:
547:
536:
534:
512:
509:
507:
503:
499:
490:
488:
473:
469:
465:
457:
453:
448:
446:
442:
438:
434:
430:
426:
422:
421:higher-energy
418:
414:
410:
406:
402:
392:
390:
382:
378:
374:
371:
368:
364:
363:
362:
360:
355:
351:
346:
344:
340:
335:
331:
327:
321:
319:
315:
310:
306:
300:
289:
279:
275:
271:
265:
264:
261:reads like a
259:This article
257:
248:
247:
239:
237:
233:
229:
225:
224:silver halide
221:
217:
211:
201:
199:
195:
191:
190:excited state
187:
183:
179:
131:
130:
129:
126:
124:
120:
112:
108:
104:
100:
92:
88:
80:
72:
68:
64:
60:
52:
47:
45:
41:
37:
33:
29:
21:
2000:
1996:
1990:
1965:
1961:
1955:
1930:
1926:
1920:
1910:
1903:
1878:10261/172782
1861:(1): 60–68.
1858:
1854:
1840:
1813:
1809:
1799:
1772:
1768:
1758:
1716:(3): 674–8.
1713:
1709:
1699:
1690:
1684:
1672:. Retrieved
1662:
1617:
1613:
1603:
1581:(4): 200–5.
1578:
1574:
1481:
1462:
1460:bacteria").
1457:
1440:
1438:
1433:
1431:
1427:
1419:
1418:
1410:
1408:
1404:
1400:
1396:
1392:
1385:
1373:
1361:
1357:
1353:
1351:
1342:
1335:
1326:
1318:
1314:
1302:
1294:
1287:
1285:
1271:
1263:
1261:
1253:
1251:
1242:
1241:
1238:plastoquinol
1237:
1233:
1229:
1221:
1219:
1216:plastoquinol
1215:
1206:
1205:
1201:
1197:
1193:
1185:
1183:
1174:
1173:
1170:plastoquinol
1169:
1165:
1150:
1142:
1137:
1124:
1119:
1110:
1108:
1096:
1075:
1071:
1041:
1039:
1032:
1030:
1026:
1019:
1015:
1006:
1005:
1001:
997:
993:
989:
986:plastocyanin
985:
977:
969:
963:
961:
929:cytochrome c
925:cytochrome b
916:
911:
904:
896:
894:
889:plastocyanin
887:
879:
862:
858:
849:
838:
834:
810:
795:
792:plastoquinol
791:
787:
785:
780:
775:
773:
761:
687:
673:
669:
665:
649:
643:
637:
633:
617:
615:
601:
599:
596:plastoquinol
595:
591:
587:
572:
564:
558:
551:
549:
528:
514:
510:
506:ATP synthase
493:
491:
464:plastocyanin
452:plastoquinol
449:
405:chloroplasts
398:
386:
347:
326:fluorescence
322:
302:
286:October 2022
283:
260:
213:
175:
127:
114:
94:
82:
54:
48:
34:involved in
30:are certain
27:
26:
1933:: 147–264.
1472:precambrian
1184:cytochrome
1144:phycobilins
1105:In bacteria
1046:ferredoxin
912:Complex III
861:cytochrome
848:Cytochrome
800:solid-state
796:picoseconds
776:P680 → P680
403:process in
357:leading to
350:picoseconds
309:chlorophyll
272:to make it
156:+ 3ADP + 3P
69:, creating
2039:Categories
1553:References
1508:Robin Hill
1428:menaquinol
1401:ferredoxin
1352:This is a
1198:ferredoxin
1034:ferredoxin
419:attains a
339:ionization
1968:: 1–114.
1947:186210131
1810:Structure
1769:Structure
1312:family).
1057:reductase
876:1.10.99.1
616:The step
216:chemistry
105:from the
2025:84721851
1982:19597530
1895:53249935
1887:30414412
1674:March 2,
1654:11038602
1595:19303349
1526:See also
441:Z-scheme
409:electron
365:Another
354:electron
334:electron
332:. If an
263:textbook
194:molecule
186:electron
2005:Bibcode
1832:8081747
1791:9438861
1750:6322162
1718:Bibcode
1622:Bibcode
1478:History
869:complex
831:Summary
764:photons
555:complex
502:protons
274:neutral
268:Please
230:in the
109:to the
103:protons
2023:
1980:
1945:
1893:
1885:
1830:
1789:
1748:
1741:344897
1738:
1652:
1642:
1593:
1458:sulfur
1354:cyclic
1348:→ P870
1341:→ cyt
1214:←
630:→ P680
472:stroma
107:stroma
71:oxygen
2021:S2CID
1978:S2CID
1943:S2CID
1891:S2CID
1645:19834
1202:NADPH
1014:←
1002:NADPH
823:(or Y
487:NADPH
445:redox
429:redox
389:NADPH
305:dimer
228:ozone
111:lumen
67:water
1883:PMID
1859:1860
1828:PMID
1787:PMID
1746:PMID
1676:2006
1650:PMID
1591:PMID
1466:and
1409:cyt
1405:NADH
1397:P840
1393:P840
1310:COX3
1262:cyt
1252:cyt
1166:PSII
1061:NADP
1048:NADP
994:P700
990:P700
592:P680
588:P680
476:NADP
417:PSII
413:P680
399:The
318:P700
314:P680
147:NADP
2013:doi
2001:127
1970:doi
1935:doi
1873:hdl
1863:doi
1818:doi
1777:doi
1736:PMC
1726:doi
1640:PMC
1630:doi
1583:doi
1439:In
1413:553
1200:→
1194:PSI
998:FNR
982:):
817:680
813:680
644:OEC
636:or
485:to
437:PSI
415:of
411:of
307:of
214:In
145:+ 2
2041::
2019:.
2011:.
1999:.
1976:.
1964:.
1941:.
1931:62
1929:.
1889:.
1881:.
1871:.
1857:.
1853:.
1826:.
1812:.
1808:.
1785:.
1771:.
1767:.
1744:.
1734:.
1724:.
1714:81
1712:.
1708:.
1648:.
1638:.
1628:.
1618:94
1616:.
1612:.
1589:.
1579:14
1577:.
1573:.
1561:^
1512:CO
1496:CO
1420:bc
1403:→
1399:→
1395:→
1362:bc
1336:bc
1303:aa
1270:→
1264:aa
1260:→
1250:→
1236:→
1196:→
1192:→
1182:→
1168:→
1164:→
1130:.
1122:.
1084:CO
1000:→
996:→
992:→
988:→
905:bc
873:EC
844:.
766:.
737:HO
672:+
670:4e
668:+
666:4H
664:→
594:→
590:→
586:→
569::
508:.
489:.
391:.
160:→
125:.
73:(O
46:.
2027:.
2015::
2007::
1984:.
1972::
1966:3
1949:.
1937::
1897:.
1875::
1865::
1849:6
1834:.
1820::
1814:2
1793:.
1779::
1773:5
1752:.
1728::
1720::
1678:.
1656:.
1632::
1624::
1597:.
1585::
1517:2
1501:2
1454:S
1450:2
1445:H
1426:←
1422:1
1417:←
1411:c
1364:1
1345:2
1343:c
1338:1
1305:3
1299:f
1297:6
1295:b
1290:6
1288:c
1278:2
1273:O
1266:3
1256:6
1254:c
1247:f
1245:6
1243:b
1240:→
1224:6
1222:c
1211:f
1209:6
1207:b
1188:6
1186:c
1179:f
1177:6
1175:b
1172:→
1161:O
1157:2
1152:H
1115:f
1113:6
1111:b
1089:2
1080:f
1078:6
1076:b
1011:f
1009:6
1007:b
976:(
974:f
972:6
970:b
949:6
947:b
931:1
921:6
917:c
910:(
907:1
901:f
899:6
897:b
884:f
882:6
880:b
867:f
865:6
863:b
854:f
852:6
850:b
825:Z
821:Z
754:2
749:O
742:2
730:2
725:O
721:2
716:H
712:O
708:2
703:H
699:O
695:2
690:H
680:2
675:O
661:O
657:2
652:H
650:2
642:(
628:O
624:2
619:H
606:f
604:6
602:b
583:O
579:2
574:H
533:f
531:6
529:b
525:O
521:2
516:H
498:f
496:6
494:b
460:6
288:)
284:(
280:.
266:.
167:2
162:O
158:i
143:O
139:2
134:H
132:2
119:f
117:6
115:b
99:f
97:6
95:b
87:f
85:6
83:b
75:2
59:f
57:6
55:b
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
