Ko kun karanci ilmin halitta a makarantar sakandare, ko kuma kuna karanta game da ribar da aka samu na tsoka, tabbas kun ji Krebs sake zagayowar. Yana daya daga cikin matakan rayuwa na numfashi na aerobic wanda yake faruwa a jikinmu. Hakanan an san shi da sunan zagayen citric acid kuma mataki ne na rayuwa wanda ke faruwa a cikin matochondrial matrix na dukkanin ƙwayoyin dabbobi.
A cikin wannan labarin za mu gaya muku abin da halaye suke, mataki-mataki sassan kewayen krebs da mahimmancinsu a matakin gaba ɗaya.
Hanyoyin numfashi na salula
Kafin mu iya bayanin menene zagayen krebs, dole ne mu tuna yadda numfashi na salula yake aiki, tunda yana da mahimmancin gaske. Bari mu ga menene fasalin numfashi na salula. Yana faruwa a cikin manyan matakai guda 3:
- Cutar Glycolysis: ita ce hanyar da ake raba glucose cikin kananan abubuwa. Yayin wannan aikin an samar da pyruvate ko pyruvic acid wanda zai haifar da Acetyl-CoA.
- Krebs sake zagayowar: A cikin zagayen Krebs, Acetyl-CoA yana da oxidized zuwa CO2.
- Sarkar numfashi: Mafi yawan makamashi ana samar dasu anan ta hanyar tura electrons daga hydrogen. Wannan makamashi ya samo asali ne daga kawar da abubuwan da ke cikin abubuwan da suka gabata.
Menene krebs sake zagayowar
Ta yaya numfashi na salula ke aiki, wanda aka haɗa shi a ɗayan matakan wannan zagayen, bari mu ga abin da yake. Mun san cewa zagaye ne mai rikitarwa kuma yana da ayyuka da yawa waɗanda ke taimakawa ƙwayar salula. Idan ba tare da wannan zagayen ba, dukkan kwayoyin halitta ba za su iya cika ayyukan da ke da muhimmanci ga jikinmu ba. Babban makasudin zagayen krebs shine a sami damar inganta lalacewar kayayyakin karshe na abubuwan da ke dauke da sinadarin carbohydrates, lipids da wasu amino acid.
Lokacin da muke cin abinci dole ne mu sani cewa manyan abubuwan gina jiki sune carbohydrates, sunadarai da mai. Sunadarai, bi da bi, sun kasance ne daga amino acid. A saboda wannan dalili, a cikin tsarin ciyarwar da zagayen krebs yana da mahimmancin gaske. Duk abubuwan da aka cinye cikin jiki ta hanyar abinci sun zama a cikin Acetyl-CoA tare da 'yantar da CO2 da H2O da kira na ATP.
Godiya ga wannan haɗin, shine inda ake samar da kuzarin da ƙwayoyin dole suyi amfani dashi don cika ayyukansu. Muna da tsaka-tsakin yanayi daban-daban a duk matakan zagayen da suke amfani da shi azaman magabata a cikin hada amino acid da sauran kwayoyin halittar. Godiya ga wannan zagayen zamu iya samun kuzari daga kwayoyin halittar abinci. Wannan makamashin da muke samu zamu iya canza shi zuwa kwayoyin don amfani dasu cikin ayyukan salula kuma zamu iya aiwatar da ayyukanmu masu mahimmanci da duk ayyukan yau da kullun na yau.
A cikin zagayen krebs mun sami wasu halayen halayen sunadarai cewa sun fi dacewa da yanayin abu. Duk halayen suna buƙatar oxygen don faruwa. Kowane tasirin sinadarai yana da haɗuwa da wasu enzymes da ake samu a cikin mitochondria na sel. Duk enzymes suna da babban sifa na iya haɓaka halayen halayen sunadarai. Lokacin da muke magana game da haɓaka wani aiki muna nufin iya ƙara ƙimar da ake jujjuya masu jujjuyawar zuwa kayan.
Matakai na zagayen krebs
Akwai halayen sunadarai da yawa yayin wannan sake zagayowar wanda ke buƙatar ɗaukar oxygen. Amfani da sinadarai na farko shi ne decarboxylation na oxyidative na pyruvate. A wannan yanayin, gulukos din da aka samu daga lalacewar hydrates na batandi ya rikide zuwa kwayoyin biyu na pyruvic acid ko pyruvate. Glucose ya kaskanta ta hanyar Glycolysis kuma ya zama muhimmiyar hanyar Acetyl-CoA. Magungunan decarboxylation na oxidative na pyruvate yana farawa tare da sake zagayowar ruwan citric acid. Wannan aikin sunadaran yayi daidai da kawar da iskar carbon dioxide da pyruvate wanda ake samarwa a cikin rukunin acetyl wanda ke ɗaure ga coenzyme A. A wannan aikin sinadaran, NADH ana samar dashi azaman kwayar halitta mai ɗaukar makamashi.
Da zarar an kirkiro kwayar Acetyl-CoA, wannan shine lokacin da zagayen kreb ke faruwa a cikin matrix na mitochondria. Makasudin wannan bangare shine a sami damar hada sarkar hada abubuwa ta sel domin a sanyaya dukkan carbin din sannan kuma a samu damar juya su zuwa iskar carbon dioxide. Don duk waɗannan halayen sunadaran su faru, kasancewar oxygen ya zama dole a kowane lokaci. Saboda haka, Mun ambata kafin fara bayanin krebs zagayowar mahimmancin numfashi na salula.
Dukkanin yana farawa tare da enzyme citrate synthetase wanda ke aiki don haɓaka haɓakar sinadarai wanda canja wurin ƙungiyar Acetyl zuwa acid oxaloacetic wanda ke samar da acid citric da sakin coenzyme A. Sunan wannan zagayen yana da alaƙa da samuwar acid citric da duk halayen sinadaran da ke faruwa anan.
Furtherarin hadawan abu da iskar shaka da halayen sake bayyana yana faruwa a cikin matakai masu zuwa. Wadannan halayen suna haifar da ketoglutaric acid ya samu. A yayin aiwatarwa, ana sakin carbon dioxide kuma ana samun NADH da H.Wannan ketoglutaric acid yana shan aikin maye gurbin dearboxylation wanda aka kara shi tare da wani sinadarin enzyme wanda Acetyl CoA da NAD ke ciki. Duk waɗannan halayen zasu haifar da acid na succinic, NADH, da kwayar GTP wanda daga baya zai canza makamashinta zuwa kwayar ADP mai samar da ATP.
Matakan ƙarshe na wannan sake zagayowar haka sun fi mai da hankali ne kawai akan cewa za a iya yin acid din succinic don yin fumaric acid. Wannan nau'in acid an san shi da sunan fumarate. Haɗin coenzyme nata shine ADF. Anan za a samar da FADH2, wanda shine kwayar jigilar makamashi. A ƙarshe, fumaric acid ba shi da daɗi don ƙirƙirar malic acid wanda aka fi sani da malate. Don ƙare da sake zagayowar krebs, Malic acid yana fara yin kwalliya don samar da oxaloacetic acid a hankali. Ta wannan hanyar, ana sake zagayowar kuma duk halayen da muka ambata sun sake faruwa daga farkon.
Ina fatan cewa tare da wannan bayanin zaku iya ƙarin koyo game da zagayen krebs da halayen sa.