Ngokuqinisekileyo kuye kwafuneka ukuba ufunde kwisifundo sebhayoloji elinye lamanqanaba emetabolism yokuphefumla kwamaselula okwenzeka emzimbeni wethu. Malunga nayo Umjikelo weKrebs. Kwakhona kwaziwa ngegama lomjikelezo we-citric acid kwaye isigaba sokuxilongwa esenzeka kwimatriki ye-mitochondrial yeseli zezilwanyana.
Kule nqaku siza kukuxelela ukuba zeziphi iimpawu kwaye siza kuchaza umjikelo we-Krebs inyathelo ngenyathelo nokubaluleka kwalo.
Ukuphefumla kweselula
Ngaphambi kokuba siqale ukucacisa ukuba yintoni umjikelo weKrebs, kufuneka sikhumbule ukuba ukuphefumla kweselula kubandakanya izigaba ezithathu. Masibone ukuba yeyiphi inqanaba ngalinye:
- IGlycolysis- Le yinkqubo apho iswekile yahlulwe yangamacandelo amancinci. Ngexesha lale nkqubo kwenziwa i-pyruvate okanye i-pyruvic acid eyakukhokelela kwi-Acetyl-CoA.
- Umjikelo weKrebsKumjikelo weKrebs, iAcetyl-CoA inyanzeliswa kwi-CO2.
- Ikhonkco lokuphefumla: apha uninzi lwamandla luveliswa kukudluliselwa kwee-elektroni ezivela kwihydrogen. La mandla avela ekuphelisweni kwezinto ezithatha inxaxheba kuwo onke amanyathelo angaphambili.
Yintoni umjikelo weKrebs
Siyazi ukuba ngumjikelo ontsonkothileyo kwaye unemisebenzi eliqela enceda imetabolism yeseli. Ngaphandle kwalo mjikelo, iiseli azinakho okanye zifeze imisebenzi ebalulekileyo. Eyona njongo iphambili kumjikelo weKrebs Kukukhuthaza ukonakala kweemveliso zokugqibela zemetabolism yee-carbohydrate, lipids kunye nezinye iiamino acid. Zonke ezi zinto zifakwe emzimbeni ngokutya ziguqulwa zaba yi-Acetyl-CoA ngokukhutshwa kwe-CO2 kunye ne-H2O kunye nokudityaniswa kwe-ATP.
Kulapho kuveliswa khona amandla ezisebenzisa iiseli ukwenza imisebenzi yazo. Phakathi kwamanqanaba awahlukeneyo omjikelo we-citric acid sifumana iindlela eziphakathi ezisetyenziswa njengabandulelayo kwi-biosynthesis ye-amino acid kunye nezinye i-biomolecule. Ngomjikelo weKrebs sifumana amandla kwiimolekyuli zokutya okuphilayo kwaye zidluliselwe kwiimolekyuli zihlala zikhuphela ngaphandle amandla okusetyenziswa kwimisebenzi yeselula. Ngala mandla sinokwenza imisebenzi yethu ebalulekileyo kunye nemisebenzi yomzimba yemihla ngemihla.
Kumjikelo weKrebs kukho ezinye zeempendulo zeekhemikhali ezichaseneyo. Zonke ezi mpendulo zifuna ioksijini ukuba yenzeke. Impendulo nganye yemichiza inokuthatha inxaxheba kwezinye ii-enzymes ezifumaneka kwimitochondria. Ezi enzymes zinoxanduva lokukhuthaza ukuphendula. Xa sithetha ngokuvuselela impendulo sibhekisa ekwandiseni isantya sayo. Zininzi izinto ezincedisayo ukusabela kweekhemikhali kwenzeka ngokukhawuleza kunesiqhelo.
Amanyathelo omjikelo weKrebs
Njengoko besesitshilo ngaphambili, kulo mjikelo kukho iindlela ezahlukeneyo zokuphendula kwemichiza ezifuna ioksijini ukuba yenzeke. Impendulo yokuqala yazo zonke i-oxidative decarboxylation ye-pyruvate. Kule mpendulo, i-glucose efunyenwe ekuthotyeni kwe-hydrate ye-bald iguqulwa ibe ziimolekyuli ezimbini zepyruvic acid okanye ipyruvate. Iswekile yathotywa ngeGlycolysis kwaye iba ngumthombo obalulekileyo we-Acetyl-CoA. I-oxidative decarboxylation ye-pyruvate iqala ngomjikelo we-citric acid. Le mpendulo yamachiza ihambelana nokupheliswa kwekhabhon diokside kunye ne-pyruvate eveliswayo kwiqela le-acetyl elibophelela kwi-coenzyme A. Kule mpendulo yamachiza, i-NADH iveliswa njengemolekyuli ethwala amandla.
Ngokubunjwa kwemolekyuli ye-Acetyl-CoA, Umjikelo weKrebs uqala kwi-matrix ye-mitochondria. Injongo kukudibanisa ikhonkco ye-oxidation yeselula ukwenza i-carbons kunye nokuziguqula zenze icarbon dioxide. Kuzo zonke ezi mpendulo zekhemikhali ufuna ubukho beoksijini. Ke ngoko, inkqubo yokuphefumla kweselula ibaluleke kakhulu.
Umjikelo we-Krebs uqala nge-enzyme ye-citrate synthetase ekhokelela ekuvuseleleni ukusabela kweekhemikhali kokudluliselwa kweqela le-Acetyl ukuya kwi-oxaloacetic acid eyenza i-citric acid kunye nokukhutshwa kwe-coenzyme A. Igama lomjikelo linxulumene nokwakheka kweasidi I-citrus kunye nazo zonke iimpendulo zamakhemikhali ezenzeka apha.
Ukuqhubela phambili i-oxidation kunye ne-decarboxylation reaction kwenzeka kula manyathelo alandelayo. Ezi mpendulo zibangela ukuba i-ketoglutaric acid yenze. Ngexesha lenkqubo, ikharbon diokside iyakhutshwa kwaye i-NADH kunye ne-H ziyenziwa.Le ketoglutaric acid ifumana i-oxidative decarboxylation reaction ethe yaphakanyiswa ngobunzima be-enzyme apho i-Acetyl CoA kunye ne-NAD ziyinxalenye. Zonke ezi mpendulo ziya kukhokelela kwi-asidi ye-succinic, i-NADH, kunye nemolekyuli ye-GTP ethi emva koko iya kugqithisela amandla ayo kwimolekyuli ye-ADP evelisa i-ATP.
Ukusuka ku-c amanyathelo okugqibela siza kubona ukuba i-asidi ye-succinic iyakudibanisa i-fumaric acid ekwabizwa ngokuba yi-fumarate. Icoenzyme yayo yi-ADF. Nantsi i-FADH2 izakwenziwa, eyenye imolekyuli ethwala amandla. Okokugqibela, i-asidi ye-fumaric ayithandeki ukuba ikwazi ukwenza i-malic acid ekwabizwa ngokuba yi-malate. Okokugqibela kumjikelo we-Krebs, i-malic acid iyakudibanisa i-oxaloacetic acid, baphinde bawuqala umjikelo. Kwakhona zonke iimpendulo ziya kwenzeka ngalo mzuzu kwaye ziqala kwakhona.
Ukubaluleka
Kukho izigidi zeempikiswano zokwazi ukuba umjikelo weKrebs ubaluleke kakhulu kulwakhiwo lobunzima bemisipha kunye nokusebenza kakuhle komzimba. Ukuze lo mjikelo usebenze ngokuchanekileyo kukho izondlo ezi-5 ezisisiseko ekufuneka umzimba wethu usebenze: thiamine, riboflavin, niacin, isinyithi, kunye ne-glutamine. Ezi ziamino acid ezisetyenziselwa ukubumba izicubu zomzimba ezintsha. Ke ngoko, kubalulekile ukuba wazi ukuba usebenza njani lo mjikelo ukuze ugxininise isondlo esifanelekileyo ukuze wandise ukusebenza kunye nobunzima bemisipha.
Kukwaluncedo ukuba wazi umjikelo weKrebs ukunqanda izifo ezininzi ngenxa yamandla okanye ukusilela kwezondlo emzimbeni wethu. Njengoko ubona, zonke ezi mpendulo zamachiza zenzeka ngaxeshanye emzimbeni ukuqinisekisa ukusebenza kakuhle.
Ndiyathemba ukuba ngolu lwazi unokufunda ngakumbi malunga nomjikelo weKrebs kunye nokubaluleka kwayo.