- photosynthesis ntoni na? sigaba photosynthesis. Imigaqo photosynthesis

Ngaba wake wazibuza ukuba zingaphi izinto eziphilayo emhlabeni? Kwaye emva koko, bonke badinga ukuphefumula i-oksijeni ukwenzela ukuvelisa amandla nokuphefumula i-carbon dioxide. I- carbon dioxide - isizathu esona sizathu saloo nto, njengobunzima kwigumbi. Kuyenzeka xa kukho abantu abaninzi kulo, kwaye igumbi alinomoya womoya ixesha elide. Ukongeza, izinto ezinetyhefu zizaliswa ngendawo yokuvelisa umoya, izithuthi ezizimeleyo kunye nezithuthi zikawonkewonke.

Ngenxa yolu ngasentla, umbuzo ocacileyo uvela: njani ukuza kwethu asisitshiywanga ukuba yonke into ephilayo ingumthombo we-carbon dioxide? Umsindisi wazo zonke izinto eziphilayo kule meko yi-photosynthesis. Iyintoni le nkqubo kunye nantoni yayo?

Isiphumo salo kukuhlengahlengiswa kwe-carbon dioxide kunye nokuzaliswa komoya kunye ne-oxygen. Inqubo enjalo iyaziwa kuphela kubameli belizwe leentyatyambo, oko kukuthi, ukuba zityalo, njengoko zenzeka kuphela kwiiseli zazo.

Ngokwalo, i-photosynthesis yinkqubo eyinkimbinkimbi kakhulu, kuxhomekeka kwiimeko ezithile kwaye ivela kwizigaba eziliqela.

Inkcazo yemeko

Ngokutsho kwenzululwazi, izinto eziphilayo kwi- processynthesis ziguqulwa zibe yizinto eziphilayo kwiqondo leselula kwizinto ezizenzekelayo nge- autotrophic organisms ngenxa yokusebenza kwelanga.

Ngolwimi oluqondakalayo, i-photosynthesis yinkqubo apho oku kulandelayo kwenzeka:

1. Isityalo sizaliswe ngumswakama. Umthombo wobumanzi unokuba ngumhlaba ovela kumhlaba okanye omanzi omoya ophezulu.
2. Kukho ukusabela kwe-chlorophyll (into ekhethekileyo ekhoyo kwisityalo) kwimpembelelo yamandla elanga.
3. Ukuqulunqwa kokutya okuyimfuneko kubameli beeflora, abangenako ukuvelisa ngokuzimeleyo i-heterotrophic, kwaye bona ngokwabo ngumvelisi walo. Ngamanye amazwi, izityalo zidla oko zizivelisayo ngokwayo. Oku kungumphumo we-photosynthesis.

Isigaba esisodwa

Cishe zonke izityalo zinezinto eziluhlaza, apho zingakwazi ukufumana ukukhanya. Le nkunkuma ayikho enye i-chlorophyll. Iindawo zakhe ezikhoyo zichloroplast. Kodwa i-chloroplast zifumaneka kwi-stem ingxenye yesityalo kunye neziqhamo zayo. Kodwa i-photosynthesis yeqabunga ixhaphake ngokukodwa kwimvelo. Ekubeni ukugqibela kunokuba kulula kwisakhiwo sayo kwaye kunomhlaba omkhulu, oku kuthetha ukuba umbane wamandla okufuneka ube ngumsebenzi wokusindiswa uya kuba omkhulu.

Xa ukukhanya kuthathwa yi-chlorophyll, lo mva uphantsi kwimeko yolonwabo kwaye udlulisela imiyalezo yamandla kwenye iimolekyuli ze-organic plant. Inani elikhulu lamandla liya kubathathi-nxaxheba kwinkqubo ye-photosynthesis.

Isigaba Sibini

Ukubunjwa kwe-photosynthesis kwinqanaba lesibini akufuneki ukuthatha inxaxheba ekubambeni kokukhanya. Iqulethwe ekubunjweni kweebhondi zeekhemikhali usebenzisa i-carbon dioxide enetyhefu, eyenziwa ngamanzi omhlaba kunye namanzi. Kwakhona, uninzi lwezinto ezihlanganisiwe, eziqinisekisa umsebenzi obalulekileyo wabameli beeflora. Ezi zinjalo isitashi, i-glucose.

Kwizityalo, ezo zinto zendalo zisebenza njengomthombo wesondlo kwiindawo ezithile zesityalo, ngelixa ziqinisekisa inkqubo eqhelekileyo yokuphila kweenkqubo. Izinto ezinjalo zifunyanwa kunye nabameli bezilwanyana ezitya izityalo zokutya. Umzimba womntu uzaliswe ngezi zinto ngokutya, okubandakanywa ekudleni kwansuku zonke.

Yintoni? Phi? Nini?

Ukuze izinto eziphilayo ziphendulwe zibe yizinto eziphilayo, kuyimfuneko ukuqinisekisa iimeko ezifanelekileyo ze-photosynthesis. Ngenxa yenkqubo ekuqwalaselwe ngayo, ukukhanya kuyadingeka kuqala. Kuthe malunga nomsebenzi, kunye nelanga. Kwizilwanyana, ngokuqhelekileyo umsebenzi wezityalo ubonakaliswa ngamandla entwasahlobo nasehlotyeni, oko kukuthi, xa kukho imfuneko enkulu yemandla elanga. Into engenakutsholwa ngexesha lekwindla, xa kunokukhanya okungaphantsi, usuku lufutshane. Ngenxa yoko, amahlamvu ajika ephuzi, aze awele ngokupheleleyo. Kodwa ngokukhawuleza ukukhanya kwelanga, i-chlorophyll iya kuphinda iqale ukusebenza kwayo, kwaye ukuveliswa kwe-oxygen kunye nezinye izondlo, ezibaluleke kakhulu, ziya kuqala.

Iimeko ze-photosynthesis azibandakanyi kuphela ubukho bokukhanya. Ukuthungwa kwakhona kufanele kube ngokwaneleyo. Emva koko, isityalo sokuqala sithatha umswakama, kwaye emva kokuqala kokuthatha inxaxheba yombane welanga. Isiphumo sale nkqubo yimiveliso yokutya yezityalo.

Ekubeni kwezinto eziluhlaza, i-photosynthesis ivela. Yintoni i-chlorophyll, esele sichazwe ngasentla. Benza njengoluhlobo lomqhubi phakathi kokukhanya okanye amandla elanga kunye nesityalo ngokwawo, ukuqinisekisa ukuhamba kakuhle kobomi babo kunye nomsebenzi. Izinto eziluhlaza zinokukwazi ukufumana ukukhanya kwelanga.

I-oksijeni inendima ebalulekileyo. Ukwenza inkqubo ye-photosynthesis iphumelele, izityalo zifuna ezininzi, kuba iqulethe kuphela i-0.03% ye-acidic acid. Ngenxa yoko, ukusuka kwi-6,000 m ³ yomoya, i-6 m ^{3 ye-} asidi ingatholakala. Yona yinto yokugqibela-eyona nto ibalulekileyo yendalo ye-glucose, eyona nto iyimfuneko ebomini.

Kukho izigaba ezimbini ze-photosynthesis. Okokuqala kukhanya, okwesibini mnyama.

Iyiphi indlela yokuhamba kwebala lokukhanya

Isigaba sokukhanya se-photosynthesis sinomnye igama-isithombe se-photochemical. Abathathi-nxaxheba abalulekileyo kweli nqanaba:

• Amandla elanga;
• Ezahlukeneyo zeehagu.

Ngenkalo yokuqala into yonke icacile, le yelanga. Yaye yile nto iingubo, kungekhona wonke umntu owaziyo. Zihlaza, ziphuzi, zibomvu okanye zihlaza okwesibhakabhaka. Ukuluhlaza kunamaqela e-chlorophyll "A" kunye ne "B", ephuzi kunye nobomvu / obomvu-phycobilin ngokulandelanayo. Umsebenzi we-photochemical phakathi kwabathathi-nxaxheba kule nqanaba kwinkqubo kubonakala kuphela nge-chlorophyll "A". Amanye ayingxenye yenkxaso ehambelanayo, ubuncinane be-quanta yokukhanya kunye nokuhamba kwabo kwiziko le-photochemical.

Ekubeni i-chlorophyll inikwe amandla okukwazi ukufumana amandla okukhanya kwelanga ngobude obude, ezi nkqubo zilandelayo:

- I-Photochemical center 1 (izinto eziluhlaza zeqela "A") - ukubunjwa kubandakanya i-pigment 700, i-ray ekhanyayo, ubude bayo malunga ne-700 nm. Le pigment iyingxenye ebalulekileyo ekudaleni iimveliso zesigaba sokukhanya se-photosynthesis.

- I-photochemical center 2 (izinto eziluhlaza zeqela "B") - ukubunjwa kubandakanya i-pigment 680, i-ray ekhanyayo, ubude obuyi-680 nm. Unayo indima yesicwangciso sesibini, ehambisana nomsebenzi wokuzaliswa kwee-elektroni ezilahlekelwe yesikhungo se-photochemical 1. Kufezekiswe ngenxa ye-hydrolysis yamanzi.

Kwii-molecule ze-350-400 zee-pigment, ezigxila kwimilambo ekhanyayo kwiimpawu zendlela ze-1 kunye ne-2, kukho enye i-molecule ye-pigment, eyona-photochemically-chlorophyll yeqela "A".

Yintoni eyenzekayo?

1. Amandla okukhanya abanjwe sisityalo ayachaphazela i-pigment 700 equlethwe kuyo, ephuma kwiimeko eziqhelekileyo ukuya kwi-excitation state. I-pigment ilahleka i-electron, eyenza ukubunjwa kwendawo ebizwa ngokuba yi-electron. Ngaphezulu, i-molecule ye-pigment, elahlekelwe i-electron, inokusebenza njengamkeliyo wayo, oko kukuthi, iqela elifumana i-electron, kwaye libuyisele umlo walo.

2. Inkqubo yokuchithwa kwe-liquid kwi-photochemical center ye-pigment absorbing 680 yesimo se-2. Xa amanzi ehla, i-electron iyakhiwa eyamkelwa yinto efana ne-cytochrome C550 kwaye ikhethwe yileta Q. Emva koko i-cytochrome, iifowuni zifaka ukhenketho lwe-vector kwaye zithunyelwa kwi-photochemical center 1 Ukuzaliswa kwe-electron hole, eyabangela ukungena kwe-quanta ekukhanyeni kunye nenkqubo yokwakhiwa kwe-pigment 700.

Kukho imeko xa i-molecule ibuyisela i-electron efana neyokuqala. Oku kuya kubangela ukukhululwa kwamandla okukhanya ngendlela yobushushu. Kodwa phantse njalo i-electron enexabiso elibi lidibanisa kwiiprotheyini ze-iron-sulfur ezikhethekileyo kwaye zithunyelwa enye kwenye yamaketanga ukuya kwi-pigment 700 okanye ziwela kwelinye ikhonkco yevectors kunye ne-reconnect kunye ne-acceptor.

Kwimeko yokuqala, ukuthuthwa kwe-cyclic ye-electron yolu hlobo oluvaliweyo kwenzeka, ngelixa le sibini, ukuthuthwa kwe-noncyclic kwenzeka.

Zombini iinkqubo ziwela kwisigaba sokuqala se-photosynthesis phantsi kwe-catalysis ngoluhlu olufanayo lwezithuthi ze-electron. Kodwa kuyafaneleka ukuba uqaphele ukuba nge-cyclophosphorylation yoluhlobo lwe-cyclic, lokuqala kunye ngexesha elifanayo lokugqibela lokuthutha i-chlophyll, ngelixa ukuhamba ngokungahambisani nokujikeleza kubonisa ukutshintshwa kwezinto eziluhlaza kweqela "B" kwi-chlorophyll "A".

Iinkalo zokuhamba ngebhayisikili

I-phosphorylation ye-cyclic ibizwa nangokuthi i-photosynthetic. Ngenxa yolu hlobo, ii-molecule ze-ATP zenziwe. Le ndlela yokuthutha isekelwe ekubuyiseni ngamanyathelo athile alandelelanayo ama-electrons kwimeko evuyayo kwi-pigment 700, ngaloo ndlela ukukhulula amandla athatha inxaxheba kwinkqubo ye-enzyme ye-phosphorylating yokuqhubeka nokuqokelela kwiibhondi ze-phosphate ze-ATP. Oko kukuthi, amandla awayekanga.

I-phosphorylation cyclic yindlela eyona nto yokuphendula ngayo i-photosynthesis, esekelwe kwi-teknoloji yokwakhiwa kwamandla ekhemikhali kwiimpawu zomlenze we-chloroplast tilaktoid ngenxa yokusetyenziswa kwamandla elanga.

Ngaphandle kwe-phosphorylation ye-photosynthetic, ukuphendulwa kwe-assimilation kwisigaba esimnyama se-photosynthesis akunakwenzeka.

Imiba yokuthutha uhlobo olungenzi-cyclic

Inkqubo ibandakanya ukubuyiswa kwe-NADP + kunye nokwakhiwa kwe-NADP * H. Inkqubo isekelwe kwi-elektron transfer transferedoxin, ukusabela kwayo yokunciphisa nokutshintshwa kwe-NADP + ngokunciphisa okuqhubekayo ku-NADP * H.

Ngenxa yoko, ii-electrons ezilahlekelwe i-pigment 700 zizaliswa yi-electrons zamanzi, ezonakalisa phantsi kwemisebe yokukhanya kwindlela yesimo 2.

Indlela yokungahambisani nomjikelezo wee-elektronon, ukuhamba kwawo oku kuthetha ukuba i-photosynthesis elula, iyaqalwa ngokusebenzisana kwezi zombini zendlela kunye neendlela zazo zokuthutha nge-electronic. Amandla okukhanya aqondisa ukuhamba kwee-elektronika. Ngethuba lokuthutha ukusuka kwi-photochemical center 1 ukuya kwisibini 2, ii-electron zilahlekelwa ezinye zamandla abo ngenxa yokuqokelela njengendlela enokwenzeka yeproton kwi-surface membrane ye-tilaktoid.

Kwisigaba esimnyama se-photosynthesis, inkqubo yokudala i-proton-type potential in chain chain transport and operation for the formation of ATP kwi-chloroplast iphantse iyafana nenkqubo efanayo kule mitochondria. Kodwa ezi zinto zikhoyo. I-Tylactoids kule meko i-mitochondria yajika kwicala elingalunganga. Esi sizathu esona sizathu sokuba i-electrons kunye neeponononi zihamba kwi-membrane kwindlela eyahlukileyo ngokumalunga nokuhamba kwezothutho kwi membrane ye-mitochondrial. Iifowuni zithunyelwa ngaphandle, kwaye iiponononi ziqokelele kwicandelo langaphakathi le-tilaktoid matrix. Umva wokugqibela uthatha inkokhelo enhle kuphela, kwaye i-membrane yangaphandle ye-tilaktoid ayibi. Kulandela ukuba indlela ye-proton-type gradient iyahluke kwindlela yayo kwimithachondria.

Uphawu olulandelayo lukhulu lwezinga le-pH kwiimeko zeeponononi.

Uphawu lwesithathu lukho ubukholu be-tilaktoid yeendawo ezimbini zokudibanisa kwaye ngenxa yoko umlinganiselo we-molecule ye-ATP kwi-proton ngu-1: 3.

Isiphelo

Kwisigaba sokuqala, i-photosynthesis yintsebenziswano yamandla okukhanya (okufakelwayo kunye nokungabonakaliyo) kunye nesityalo. Ukuphendula kwimida yezinto eziluhlaza - i-chlorophyll, ininzi yayo equlethwe kumagqabi.

Ukubunjwa kwe-ATP kunye ne-NADP * H yiphumo lo mpendulo. Ezi mveliso ziyimfuneko ekuhambeni kwemibono emnyama. Ngoko ke, indawo yokukhanya yinkqubo enyanzelekileyo, ngaphandle kweyiphi na isigaba sesibini asiyi kuqhubeka-emnyama.

Isigaba somnyama: isitshixo kunye neempawu

I-photosynthesis ebumnyama kunye nokuphendula kwayo yinkqubo ye-carbon dioxide kwimveliso yendalo evela kwimveliso ye-carbohydrates. Ukuphendula okunjalo kwenzeka kwi-stroma ye-chloroplast kunye nemveliso yesigaba sokuqala se-photosynthesis, ukukhanya, ukuthatha inxaxheba ebonakalayo kubo.

Inkqubo yendawo ebumnyama ye-photosynthesis isekelwe kwinkqubo yokwenziwa kwe-carbon dioxide (ebizwa nangokuthi i-photochemical carboxylation, umjikelezo weCalvin), ebonakalayo ngokuhamba nge-cyclicity. Iqukethe izigaba ezintathu:

1. I-Carboxylation yongezwa yi-CO ₂ .
2. Isigaba sokubuyisela.
3. Isigaba sokuvuselelwa kwe-ribulosodiphosphate.

I-Ribulophosphate, ishukela ezinama-athobhoni amahlanu e-carbon, inokubangela ukuba i-phosphorylation i-ATP, ekhokelela ekubunjweni kwe-ribulosodiphosphate, eqhutyelwa phambili kwi-carboxylation ngokudibanisa nomkhiqizo we-CO ₂ kunye neetakhanqatha ezithandathu ezithinteka ngokukhawuleza ngokusabela nge-molecule yamanzi, ukudala ezimbini i-molecular acid particles of phosphoglycerol . Emva koko le asidi ihamba ngekhondo lokunciphisa okupheleleyo ngexesha le-enzymatic reaction, apho ubukho be-ATP kunye ne-NADPH bubalulekile ukwenza iswekile kunye neethathu i-carbons, i-triote okanye i-aldehyde ye-phosphoglycerol. Xa ezi zimbini zihlenga, i-molecule ye-hexose ifunyenwe ibe yinxalenye ebalulekileyo yekimleksi ye-starch kwaye igqitywe kwi-molecule.

Esi sigaba sigqityiweyo kukuba ngexesha le-photosynthesis, enye i-molecule ye-CO ₂ ixutywe kwaye i-molecule ye-ATP kunye nee-athomu ze-N ezine zisetyenzisiweyo. I-hexose phosphate isabela kwiimpendulo ze-pentosis phosphate cycle, ngenxa yoko kuveliswa kwakhona i-ribulose phosphate, enokuphinde iphinde ihlangane nomnye i-molecule ye-carbonic acid.

Ukuphendula kwe-carboxylation, ukunciphisa, ukuhlaziywa kwakhona akunakubizwa ngokuba yi-cell kuphela apho i-photosynthesis yenzeka khona. Naluphi uququzelelo "olufanayo" lwenkqubo, kwakhona, akunakutsholwa, kuba ukwahlukana kusekhona - kwinkqubo yokubuyisela, i-NADP * H isetyenzisiweyo, kwaye ayiyi NAD * N.

Ukongezwa kwe-CO _{2 yi-} ribulosodiphosphate ilawulwa ngu-ribulose diphosphate carboxylase. Imveliso yokusabela i-3-phosphoglycerate, eyancitshiswa yi-NADP * H2 ne-ATP kwi-glyceraldehyde-3-phosphate. Inkqubo yokunciphisa i-catalyzed glyceraldehyde-3-phosphate dehydrogenase. Olu hlobo lokugqibela luguqulwa kwi-dihydroxyacetone iphosphate. I-Fructose-bisphosphate yenziwa. Ezinye zeamoleksi zawo zithatha inxaxheba kwinkqubo yokuvuselela i-ribulosodiphosphate, ukuvala umjikelezo, kwaye inxalenye yesibini isetyenziselwa ukwenza iivenkile ze-carbohydrates kwiiseli ze-photosynthetic, oko kukuthi, i-photosynthesis ye-carbohydrate yenzeka.

Amandla okukhanya ayimfuneko kwi-phosphorylation kunye nokuhlanganiswa kwezinto ezivela kwimvelaphi yezinto eziphilayo, kwaye amandla okwenziwa kwe-oxidation yezinto eziphilayo kubalulekile kwi-phosphorylation ye-oxidative. Yingakho izilwanyana zinika ubomi kwizilwanyana kunye nezinye izinto eziphilayo.

I-Photosynthesis kwisitya sesityalo senziwa ngale ndlela. Imveliso yayo i-carbohydrate, efunekayo ekudaleni iibhakethi zeekhabhoni zezinto ezininzi zabameli behlabathi, ezivela kwimvelo.

izinto nitrogen Organic wendele uhlobo eziphilayo photosynthesis yi ukuncitshiswa nitrate ezingaphiliyo, nesalfure - ngenxa ekunciphiseni sulfates kumaqela sulfhydryl ye asidi acid. Ibonelela ukuyilwa iiprothini, nucleic, lipids, iikhabhohayidrethi, cofactors photosynthesis. Yintoni i "Isithebe" kwezinto kubalulekile ukuba isityalo sele wagxininisa, kodwa iimveliso kuyondelelaniswe zasesekondari ukuba izinto ezixabisekileyo amayeza (flavonoids, sezakhi, terpenes, polyphenols, steroids, orgkisloty kunye nabanye), bathi hayi ilizwi. Ngoko ke, akukho Asikokubaxa izinto ukuthi photosynthesis - isitshixo nobomi kwezityalo, izilwanyana kunye nabantu.