I-photosynthesis yinkqubo apho ubomi, njengoko siyazi, bunokubakho. Ayizizo izityalo kuphela ezixhamlayo, kodwa nezilwanyana kuba siphefumla ioksijini, irhasi egxothwa ngamagqabi.
Kuyathakazelisa kakhulu ukwazi kubunzulu be-photosynthesis, kuba kukho izigaba ezininzi, kwaye kukho ezinye izityalo, ngenxa yeemeko zemozulu abahlala kuyo, bafunde ukuyenza ngendlela eyahlukileyo.
Yintoni ifotosinthesisi?
La ifotosinthesis yinkqubo apho izityalo ziguqula ukukhanya kwelanga kube ngamandlake, bayenza emini kuphela. Abo bajongene nokufezekisa lo msebenzi ubalulekileyo ngabo ii-chloroplast, eziyizakhiwo eziluhlaza ezifumaneka emagqabini.
Umbala wabo ubangelwa yiklorofili, eyi-biomolecule ngaphandle kobukumkani besityalo obungenako ukwenza ifotosinthesize. Kubaluleke kakhulu ukuba izityalo ezinamagqabi ahlukeneyo (okt eluhlaza kunye nomthubi umzekelo) zikhula kancinci kancinci kunalawo anamagqabi aluhlaza kwaphela. Ukongeza, zisengozini yokukhanya kwelanga, zivutha ngokukhawuleza kunalezo ziluhlaza.
Inkqubo ye-photosynthesis yezityalo imi ngolu hlobo lulandelayo:
Umfanekiso - Wikimedia / Meily Poot
Zithini izigaba zefotosinthesisi kwizityalo?
Njengoko besikulindele ekuqaleni, i-photosynthesis inezigaba ezibini, zezi:
Isigaba sokukhanya
Isigaba sokukhanya sesinye esenzeka emini. Singathi yifotosinthesisi uqobo; hayi ilize, kunjalo ngexesha lomhla xa ilanga liphezulu kwaye ngenxa yoko xa izityalo zinokufunxa amandla alo okukhanya.
Kuquka ukuguqula oko kukhanya kube ngamandla, ikakhulu ngohlobo lwe-ATP (adenosine triphosphate) kunye ne-NADPH (nicotinamide adenine dinucleotide phosphate), ngoncedo lwamanzi neoksijini ethi iingcambu kunye namagqabi azifunxe ngokwahlukeneyo.
Isigaba esimnyama
La isigaba esimnyama isigaba sokugqibela sefotosinthesisi, kunye Inokuguqula ikhabhon diokside kunye nezinye izinto zibe siswekileOko kukuthi kukutya kwezityalo.
Ukwenza oku, basebenzisa zombini i-ATP kunye ne-NADPH eveliswe kwisigaba sokukhanya, kwaye baphinde benze ezinye iinkqubo ezimbini: ukulungiswa kwekhabhoni kwii-carbohydrate, kunye nomjikelo kaCalvin. Kule nkqubo yokugqibela, izinto eziphilayo zigcinwa njengeglucose.
Ngaba zonke izityalo zenza ifotosinthesize ngendlela efanayo?
Akunjalo ngokwenene. Ngapha koko, kuxhomekeke kwindlela abayilungisa ngayo ikhabhon, zintathu iintlobo zezityalo ezichongiweyo:
- C3 izityalo: zezi zilungisa ikhabhon dioksayidi kumjikelo kaCalvin. Zizinto eziqhelekileyo.
- C4 izityaloInto abayenzayo kukuguqula ikhabhon dioksayidi ibe yi-malate, eya kusiwa kwiiseli ezivelisa i-CO2 kunye ne-pyruvate. Kungoko kuphela apho umjikelo kaCalvin uza kuqala. Olunye ulwazi.
- Izityalo zeCAM: Zizityalo ezithi, ngenxa yamaqondo obushushu aphezulu emini, zigcine ii-pores zazo zivaliwe kude kube sebusuku. Ngenxa yoko, abanakho ukufunxa ikharbon diokside kwaye ngenxa yoko i-photosynthesize. Ke, bayayifunxa ngexesha lasebusuku beguqula ibe lilize, ethi emini ibenze bakwazi ukuvelisa i-CO2 kwaye benze umjikelo kaCalvin. Olunye ulwazi.
Yintoni umsebenzi wefotosinthesisi?
Ngokusisiseko kwi utshintshe amandla elanga abe kukutya kwezityalo ngothotho lweempendulo zamachiza apho zingasebenzisi ukukhanya kwelanga kuphela, kodwa nekharbon diokside kunye namanzi. Ngenxa yoko, bakhupha ioksijini, igesi leyo sonke sixhomekeke ekuphefumlweni.
Ngoku, kubalulekile ukucacisa ukuba ukugxothwa kwe-O2 akubalwa njengomsebenzi, kodwa ngenxa yefotosinthesisi. Izilwanyana, kubandakanya nabantu, zixhomekeke kubukumkani bezityalo ukuze zibekhona. Kodwa, kungakothusa ukwazi ukuba, nangona izityalo zasemhlabeni zibaluleke kakhulu ebomini, ukuba kufuneka sithi yeyiphi into ephilayo evelisa eyona oksijini ininzi, singothuka.
I-Phytoplankton, umvelisi ukuya kuthi ga kwi-85% yeoksijini yomoya
Ewe, i-phytoplankton, izinto eziphilayo kwindawo ezihlala emanzini (ulwandle, imigxobhozo, imilambo), ethi, ngokufunxa amandla elanga, yenze ifotosinthesisi, ikhuphe ioksijini. Uninzi lwezinto eziyenzayo yi-cyanobacteria, i-algae eluhlaza kunye idayom.
Ngoko ke, bona hayi amahlathi sisiseko sobomi. Kodwa kungekuphela ngenxa yeoksijini, kodwa nangenxa yokuba amatyathanga okutya aqala ngawo. Naluphi na utshintsho olwenzeka emanzini, njengokufudumeza, okanye i-asidi, luya kubathintela ekwenzeni imisebenzi yabo ngesiqhelo.
Phytoplankton ivelisa ngaphezulu kwesiqingatha seoksijini ekhoyo kulo mhlabaYiyo loo nto kubaluleke kakhulu ukukhathalela iilwandle, kodwa kunye nomhlaba okusingqongileyo, kuba asinakulibala ukuba ukugawulwa kwamahlathi kunye nongcoliseko zizinto ezibangela ukuba utshintsho lwemozulu lukhawuleze.
Siyathemba ukuba yonke into oyifundileyo malunga nefotosinthesisi iluncedo kuwe.