Umjikelezo weKrebs

Umjikelezo weKrebs

Noma ngabe ufunde i-biology esikoleni esiphakeme, noma ufunda ngokuzuza kwemisipha, uzwile ngakho Umjikelezo weKrebs. Yisinye sezigaba zokuthamba kokuphefumula kwamaselula okwenzeka emzimbeni wethu. Kuyaziwa nangegama lomjikelezo we-citric acid futhi kuyisigaba semethabolic esenzeka kumatrix we-mitochondrial wawo wonke amaseli ezilwane.

Kulesi sihloko sizokutshela ukuthi yiziphi izici, igxathu negxathu izingxenye zomjikelezo wama-krebs nokubaluleka kwawo ezingeni elijwayelekile.

Izigaba zokuphefumula kwamaselula

mitochondria

Ngaphambi kokuthi sichaze ukuthi yini umjikelezo wama-krebs, kufanele sikhumbule ukuthi ukuphefumula kwamaselula kusebenza kanjani, ngoba kubaluleke kakhulu. Ake sibone ukuthi yiziphi izigaba zokuphefumula kwamaselula. Kwenzeka ngezigaba ezintathu eziyinhloko:

  • I-Glycolysis: kuyinqubo lapho i-glucose yehlukaniswa yaba izingxenye ezincane. Phakathi nale nqubo kwakhiwa i-pyruvate noma i-pyruvic acid ezoholela ku-Acetyl-CoA.
  • Umjikelezo weKrebs: Emjikelezweni weKrebs, i-Acetyl-CoA ixhunywe ku-CO2.
  • Uchungechunge lokuphefumula: Lapha amandla amaningi akhiqizwa ngokudluliswa kwama-electron avela ku-hydrogen. La mandla avela ekususweni kwezinto ezibandakanyekayo kuzo zonke izinyathelo zangaphambilini.

Uyini umjikelezo wama-krebs

krebs umjikelezo ukusabela

Kusebenza kanjani ukuphefumula kwamaselula, okufakwe kwesinye sezinyathelo zalo mjikelezo, ake sibone ukuthi imayelana nani. Siyazi ukuthi kungumjikelezo onzima futhi unemisebenzi eminingi esiza imetabolism yeselula. Ngaphandle kwalo mjikelezo, wonke amaseli abengeke akwazi ukufeza imisebenzi ebalulekile emzimbeni wethu. Inhloso enkulu yomjikelezo wama-krebs ukukwazi ukukhuthaza ukuwohloka kwemikhiqizo yokugcina yemethabolism yama-carbohydrate, lipids namanye ama-amino acid.

Lapho sidla ukudla kufanele sazi ukuthi ama-macronutrients amakhulu ama-carbohydrate, amaprotheni namafutha. Amaprotheni nawo akhiwa ama-amino acid. Ngalesi sizathu, kwinqubo yokondla umjikelezo wama-krebs ubaluleke kakhulu. Zonke izinto ezifakwe emzimbeni ngokudla ziba ku-Acetyl-CoA ngenkululeko ye-CO2 ne-H2O nokuhlanganiswa kwe-ATP.

Ngenxa yalokhu kuhlanganiswa, kulapho kukhiqizwa khona amandla okufanele asetshenziswe amaseli ukwenza imisebenzi yawo. Sinabaxhumanisi abahlukahlukene kuzo zonke izigaba zomjikelezo abazisebenzisayo njengezandulela ekuhlanganisweni kwama-amino acid namanye ama-biomolecule. Ngenxa yalo mjikelezo singathola amandla kuma-molecule wokudla okuphilayo. La mandla esiwatholayo singawadlulisela kuma-molecule ukuze asetshenziswe emisebenzini yeselula futhi singenza imisebenzi yethu ebalulekile nayo yonke imisebenzi ebonakalayo yosuku lwethu usuku nosuku.

Ngaphakathi komjikelezo wama-krebs sithola ukuphendula okuthile kwamakhemikhali ikakhulukazi i-oxidative emvelweni. Konke ukusabela kudinga umoya-mpilo ukuze kwenzeke. Ukuphendula ngakunye kwamakhemikhali kunokubamba iqhaza kwamanye ama-enzyme atholakala kwi-mitochondria yamaseli. Onke ama-enzyme anesici esikhulu sokukwazi ukuvuselela ukusabela kwamakhemikhali. Uma sikhuluma ngokunciphisa ukusabela sikhuluma ngokwazi ukukhuphula izinga lapho ama-reactants aguqulwa abe yimikhiqizo.

Izinyathelo zomjikelezo wama-krebs

ukusabela kwamakhemikhali

Kunokuphendula okuningana kwamakhemikhali phakathi nalo mjikelezo odinga ukwenziwa komoya-mpilo. Ukusabela kokuqala kwamakhemikhali yi-decodboxylation ye-oxidative ye-pyruvate. Kulokhu kusabela, i-glucose etholakala ekonakaleni kwama-hydrate anempandla iguqulwa ibe ngama-molecule amabili we-pyruvic acid noma i-pyruvate. Iglucose yehliswa ngeGlycolysis futhi iba ngumthombo obalulekile we-Acetyl-CoA. I-oxidative decarboxylation ye-pyruvate iqala ngomjikelezo we-citric acid. Lokhu kusabela kwamakhemikhali kufana nokuqedwa kwe-carbon dioxide ne-pyruvate ekhiqizwa eqenjini le-acetyl elibophezela ku-coenzyme A. Kule mpendulo yamakhemikhali, i-NADH ikhiqizwa njengemolekyuli ethwala amandla.

Lapho i-molecule ye-Acetyl-CoA isakhiwe, kulapho umjikelezo we-kreb wenzeka matrix we-mitochondria. Inhloso yale ngxenye ukukwazi ukuhlanganisa uchungechunge lwe-oxidation yeselula ukuze ixube wonke ama-carbons futhi ukwazi ukuwaguqula abe yi-carbon dioxide. Ukuze kwenzeke konke lokhu kuphendula kwamakhemikhali, ubukhona be-oxygen buyadingeka ngaso sonke isikhathi. Ngakho-ke, Sishilo ngaphambi kokuqala ukuchaza umjikelezo wama-krebs ukubaluleka kokuphefumula kwamaselula.

Konke kuqala nge-enzyme citrate synthetase esebenza ukuvuselela ukuphendula kwamakhemikhali lapho kudlulisela khona iqembu le-Acetyl ku-oxaloacetic acid eyakha i-citric acid kanye nokukhishwa kwe-coenzyme A. Igama lalo mjikelezo lihlobene ukwakheka kwe-citric acid nakho konke ukuphendula kwamakhemikhali okwenzeka lapha.

Ukuqhubeka kokuxhuma kanye nokusabela kwe-decarboxylation kwenzeka kulezi zinyathelo ezilandelayo. Lokhu kusabela kudala i-ketoglutaric acid. Ngesikhathi kwenziwa le nqubo, kukhishwa i-carbon dioxide bese kwakhiwa i-NADH ne-H. Le ketoglutaric acid ibhekana ne-oxidative decarboxylation reaction ehlanganiswa ne-enzyme complex lapho i-Acetyl CoA ne-NAD beyingxenye yayo. Konke lokhu kuphendula kuzoholela ku-acid ye-succinic, i-NADH, ne-molecule ye-GTP ezodlulisela amandla ayo kwi-molecule ye-ADP ekhiqiza i-ATP.

Izinyathelo zokugcina zalo mjikelezo ngakho bagxila kuphela eqinisweni lokuthi i-acid ye-succinic ingaxutywa ukuze yenze i-fumaric acid. Lolu hlobo lwe-asidi lwaziwa ngegama le-fumarate. I-coenzyme yayo yi-ADF. Lapha kuzokwakhiwa i-FADH2, engenye ye-molecule yamandla othwala amandla. Ekugcineni, i-fumaric acid ayimnandi ukukwazi ukwakha i-malic acid eyaziwa nangokuthi i-malate. Ukuqeda umjikelezo wama-krebs, I-malic acid iqala ukufaka i-oxidize ukuze yenze kancane kancane i-oxaloacetic acid. Ngale ndlela, umjikelezo uqalwa phansi futhi konke ukusabela esikubalulile kwenzeka futhi kusukela ekuqaleni.

Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi ngomjikelezo wama-krebs nezici zawo.


Okuqukethwe yi-athikili kunamathela ezimisweni zethu ze izimiso zokuhlelela. Ukubika iphutha chofoza lapha.

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  1. Ubhekele imininingwane: Miguel Ángel Gatón
  2. Inhloso yedatha: Lawula Ugaxekile, ukuphathwa kwamazwana.
  3. Ukusemthethweni: Imvume yakho
  4. Ukuxhumana kwemininingwane: Imininingwane ngeke idluliselwe kubantu besithathu ngaphandle kwesibopho esisemthethweni.
  5. Isitoreji sedatha: Idatabase ebanjwe yi-Occentus Networks (EU)
  6. Amalungelo: Nganoma yisiphi isikhathi ungakhawulela, uthole futhi ususe imininingwane yakho.