I-phosphorylation ye-oxidative: ukuthuthwa kwama-electron kanye ne-chemiosmosis

I-Oxidative Phosphorylation: Ukuthuthwa kwe-Electron kanye ne-Chemiosmosis

I-oxidative phosphorylation inqubo ebalulekile ekusebenzeni kwamaseli okwenzeka ku-mitochondria. Le nqubo inesibopho sokukhiqiza iningi le-adenosine triphosphate (ATP), i-molecule enikeza amandla okusabela okuhlukahlukene kwamakhemikhali emaseli. I-oxidative phosphorylation inezigaba ezimbili eziyinhloko: uchungechunge lokuthuthwa kwama-electron kanye ne-chemiosmosis. Zombili zisebenza ndawonye ukuguqula amandla avela kwizakhamzimba ezidliwayo abe izinhlobo zamandla ezisebenzisekayo zamaseli.

Ukuthuthwa kwe-Electron

Ukuthuthwa kwama-electron kwenzeka kulwelwesi lwangaphakathi lwe-mitochondrial. Lolu lwelwesi luqukethe ama-protein complexes amahlanu asebenza ndawonye ukuhambisa ama-electron kusuka kubanikeli bama-electron njenge-NADH ne-FADH2 kuya ku-electron acceptor yokugcina, i-oxygen. Le nqubo ikhipha amandla, asetshenziselwa ukupompa ama-proton (H+) ngaphesheya kwelwelwesi lwe-mitochondrial kusuka ku-matrix kuya esikhaleni se-intermembrane, okudala i-proton gradient.

I-Complex I: I-NADH-Dehydrogenase

Inqubo yokuthutha ama-electron iqala ku-Complex I, eyaziwa nangokuthi i-NADH dehydrogenase. I-NADH ekhiqizwa emjikelezweni we-Krebs inikela ngama-electron kule complex. Ama-electron adluliselwa ngama-cofactor amaningana, kufaka phakathi i-FMN (i-flavin mononucleotide) kanye namaqoqo amaningana e-iron-sulfur. Phakathi nale nqubo, ama-proton amane adonswa kusuka ku-matrix aye esikhaleni se-intermembrane.

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I-Complex II: I-Succinate Dehydrogenase

I-Complex II yi-succinate dehydrogenase, nayo ehlanganyela emjikelezweni we-Krebs. Le complex ithola ama-electron avela ku-FADH2, ikhiqize i-FAD, futhi ikhipha ama-electron ku-ubiquinone (i-coenzyme Q). Ngokungafani ne-Complex I, i-Complex II ayipompi ama-proton kulo lonke ulwelwesi lwe-mitochondrial.

I-Complex III: I-Cytochrome bc1

I-Complex III, noma i-cytochrome bc1, yamukela ama-electron avela ku-ubiquinol (i-ubiquinone encishisiwe) bese iwadlulisela ku-cytochrome c, iphrotheni encane encibilikayo esikhaleni se-intermembrane. I-Complex III iphinde isize ukupompa kwama-proton esikhaleni se-intermembrane, okwengeza ku-gradient ye-proton esunguliwe.

I-Complex IV: I-Cytochrome c Oxidase

I-Complex IV, noma i-cytochrome c oxidase, iyisinyathelo sokugcina ochungechungeni lokuthuthwa kwama-electron. Ama-electron adluliselwa kusuka ku-cytochrome c aye ku-oxygen, i-electron acceptor yokugcina, akha amanzi. Le nqubo ihambisana nokupompa kwama-proton esikhaleni se-intermembrane.

Indima ye-Ubiquinone ne-Cytochrome c

I-Ubiquinone kanye ne-cytochrome c zisebenza njengabathwali bama-electron ahambayo. I-Ubiquinone ithatha ama-electron kusuka ku-Complexes I kanye ne-II bese iwayisa ku-Complex III. Okwamanje, i-cytochrome c ithwala ama-electron kusuka ku-Complex III kuya ku-Complex IV, okwenza inqubo yokudlulisa ama-electron iqhubeke kahle.

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I-Chemiosmosis

I-Chemiosmosis inqubo esebenzisa i-proton gradient ekhiqizwa ngesikhathi sokuthuthwa kwama-electron ukuze ikhiqize i-ATP. Le ndlela ilawulwa yi-ATP synthase, i-enzyme etholakala kulwelwesi lwangaphakathi lwe-mitochondrial.

I-Proton Gradient kanye ne-ATP Synthase

I-gradient ye-proton eyakheka ngesikhathi sokuthuthwa kwama-electron idala amandla e-electrochemical avame ukubizwa ngokuthi amandla e-proton-motive. Lokhu kunamandla kubuyisela ama-proton ku-matrix ye-mitochondrial nge-ATP synthase, esebenzisa lokhu kugeleza ukuguqula i-ADP kanye ne-phosphate engaphili ibe yi-ATP.

Isakhiwo kanye nomsebenzi we-ATP Synthase

I-ATP synthase inezingxenye ezimbili eziyinhloko: i-F0 kanye ne-F1. I-F0 yakha isiteshi se-proton ngaphesheya kwe-mitochondrial membrane, kuyilapho i-F1 isebenza njengendawo yokulungisa ukwakheka kwe-ATP. Ukugeleza kwama-proton nge-F0 kubangela ukujikeleza kwengxenye ye-F1, okuvumela izinguquko zokwakheka ezidingekayo ukubopha i-ADP kanye ne-phosphate, bese kwakha i-ATP.

Ukulawulwa kanye Nokusebenza Kahle Kwe-Oxidative Phosphorylation

Inqubo ye-oxidative phosphorylation ilawulwa yizidingo zamandla eseli. I-ATP, i-ADP, kanye ne-phosphate engaphili kudlala indima ebalulekile kulo mthethonqubo. Amazinga aphezulu e-ATP ayayibambezela le nqubo, kuyilapho amazinga aphezulu e-ADP eyisheshisa.

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Ukusebenza kahle kwamandla kwe-oxidative phosphorylation nakho kuyathakazelisa. I-molecule ngayinye ye-NADH efakwe oxidized ku-electron transport chain ingakhiqiza cishe i-2.5 ATP, kuyilapho i-FADH2 ikhiqiza cishe i-1.5 ATP. Nakuba ingasebenzi kahle nge-100%, i-oxidative phosphorylation ingumthombo oyinhloko wokukhiqizwa kwe-ATP kumaseli e-aerobic.

Imiphumela Yezokwelapha

Ukungasebenzi kahle kwe-oxidative phosphorylation kungaholela ezifweni ezahlukahlukene ze-mitochondrial, ezivame ukuthinta izitho zomzimba ezidinga amandla aphezulu, njengemisipha nobuchopho. Lezi zinkinga zingabangelwa ukuguquka kwezakhi zofuzo noma yizici zangaphandle, njengobuthi obuvimbela uchungechunge lokuthuthwa kwama-electron.

Isibonelo, i-cyanide ne-carbon monoxide zivimbela i-Complex IV, evimba ukugeleza kwama-electron kanye nokukhiqizwa kwe-ATP, okuholela ekulimaleni kwezicubu ezibalulekile zezitho ngenxa yokushoda kwamandla.

Isiphetho

I-oxidative phosphorylation inqubo ebalulekile esebenzisa ukuthuthwa kwama-electron kanye ne-chemiosmosis ukukhiqiza i-ATP, umthwali wamandla oyinhloko emaseli. Ukuqonda izindlela zayo akubalulekile nje kuphela kwibhayoloji eyisisekelo kodwa futhi kuvula umnyango wokuthuthukisa izindlela zokwelapha izifo ezihlobene nalesi sifo se-metabolic. Ukuqhubeka nokuhlola izici zama-molecule ze-oxidative phosphorylation kuzosiza abacwaningi ukuthola izixazululo ezintsha zezinkinga zempilo yabantu.

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