Oxidative Phosphorylation: Kutakura Maerekitironi uye Chemiosmosis
Kusanganiswa kwemasero (oxidative phosphorylation) inzira inokosha mukugadzirwa kwemasero mumitochondria. Maitiro aya ndiwo anokonzera kugadzirwa kweadenosine triphosphate (ATP), iyo molecule inopa simba rekuita zvakasiyana-siyana zvemakemikari mumasero. Kusanganiswa kwemasero mumasero kune zvikamu zviviri zvikuru: cheni yekufambisa maerekitironi uye chemiosmosis. Zvose zvinoshanda pamwe chete kushandura simba kubva muzvinovaka muviri zvinopinda mumasero kuita simba rinoshanda kumasero.
Kutakura Maerekitironi
Kutakurwa kwemaerekitironi kunoitika mumukati memitochondrial membrane. Kamudzira aka kane mapuroteni mashanu anoshanda pamwe chete kufambisa maerekitironi kubva kuvanopa maerekitironi vakaita seNADH neFADH2 kuenda kumagetsi ekupedzisira anogamuchira, okisijeni. Maitiro aya anoburitsa simba, iro rinoshandiswa kupomba mapurotoni (H+) kuburikidza nekamudzira kemitochondrial kubva pa matrix kuenda kunzvimbo yepakati pemembrane, zvichigadzira proton gradient.
Complex I: NADH-Dehydrogenase
Maitiro ekufambisa maerekitironi anotanga muComplex I, inozivikanwawo seNADH dehydrogenase. NADH inogadzirwa muKrebs cycle inopa maerekitironi kune iyi complex. Maerekitironi anotamiswa kuburikidza nehuwandu hwema cofactors, anosanganisira FMN (flavin mononucleotide) uye mamwe ma iron-sulfur clusters. Munguva iyi, mapurotoni mana anopombwa kubva mu matrix kuenda munzvimbo yepakati pemembrane.
Complex II: Succinate Dehydrogenase
Complex II i succinate dehydrogenase, iyo inobatawo chikamu muKrebs cycle. Complex iyi inogamuchira maerekitironi kubva kuFADH2, inogadzira FAD, uye inoburitsa maerekitironi ku ubiquinone (coenzyme Q). Kusiyana neComplex I, Complex II haipombi mapurotoni kuburikidza ne membrane ye mitochondrial.
Dambudziko rechitatu: Cytochrome bc1
Complex III, kana kuti cytochrome bc1, inogamuchira maerekitironi kubva kuubiquinol (ubiquinone yakaderedzwa) uye inoaendesa kucytochrome c, puroteni diki inonyungudika munzvimbo yepakati pemembrane. Complex III inobatsirawo kupomba mapurotoni munzvimbo yepakati pemembrane, zvichiwedzera kugadzika kweproton gradient.
Complex IV: Cytochrome c Oxidase
Complex IV, kana kuti cytochrome c oxidase, ndiyo danho rekupedzisira muketani yekufambisa maerekitironi. Maerekitironi anotamiswa kubva kucytochrome c kuenda kuokisijeni, iyo inogamuchira maerekitironi ekupedzisira, achigadzira mvura. Maitiro aya anoperekedzwawo nekupomba mapurotoni munzvimbo yepakati pemembrane.
Basa reUbiquinone neCytochrome c
Ubiquinone ne cytochrome c zvinoshanda senzira dzekutakura maerekitironi dzinofamba. Ubiquinone inotora maerekitironi kubva kuComplexes I neII yozoaendesa kuComplex III. Panguva iyi, cytochrome c inotakura maerekitironi kubva kuComplex III kuenda kuComplex IV, zvichiita kuti maitiro ekutamisa maerekitironi afambe zvakanaka.
Chemiosmosis
Chemiosmosis inzira inoshandisa proton gradient inogadzirwa panguva yekufambisa maerekitironi kugadzira ATP. Iyi nzira inodzorwa neATP synthase, enzyme iri mumukati memitochondrial membrane.
Proton Gradient uye ATP Synthase
Kuyerera kweproton kunoumbwa panguva yekufambisa maerekitironi kunogadzira electrochemical potential inowanzonzi proton-motive potential. Simba iri rinodzosa mapurotoni mu mitochondrial matrix kuburikidza neATP synthase, iyo inoshandisa kuyerera uku kushandura ADP ne inorganic phosphate kuita ATP.
Maumbirwo uye Basa reATP Synthase
ATP synthase ine zvikamu zviviri zvikuru: F0 naF1. F0 inoumba proton channel kuburikidza ne mitochondrial membrane, nepo F1 inoshanda senzvimbo inokonzeresa kugadzirwa kweATP. Kuyerera kwemaproton kuburikidza neF0 kunokonzera kutenderera kwechikamu cheF1, zvichibvumira shanduko dzechimiro dzinodiwa kuti dzisunge ADP nephosphate, uye dzigadzire ATP.
Mutemo uye Kushanda kweOxidative Phosphorylation
Maitiro e oxidative phosphorylation anodzorwa nezvinodiwa nesimba remasero. ATP, ADP, uye inorganic phosphate zvinoita basa guru mukutonga uku. Kuwanda kweATP kunononotsa maitiro aya, ukuwo kuwedzera kweADP kuchikurumidzisa.
Kushanda zvakanaka kwesimba re oxidative phosphorylation kunonakidzawo. Morekuru yega yega yeNADH yakasanganiswa muketani yekufambisa maerekitironi inogona kugadzira ATP inosvika 2.5, nepo FADH2 ichigadzira ATP inosvika 1.5. Kunyangwe isiri kushanda zvakanaka 100%, oxidative phosphorylation ndiyo inonyanya kukonzera kugadzirwa kweATP mumasero e aerobic.
Zvinokonzera Kurwara
Kusashanda zvakanaka kwe oxidative phosphorylation kunogona kukonzera zvirwere zvakasiyana-siyana zve mitochondrial, izvo zvinowanzo kanganisa nhengo dzine simba rakawanda, zvakaita semhasuru neuropi. Matambudziko aya anogona kukonzerwa nekuchinja kwemajini kana nezvinhu zvekunze, zvakaita sechepfu inodzivisa kufambisa maerekitironi.
Semuenzaniso, cyanide necarbon monoxide zvinodzivisa Complex IV, iyo inomisa kuyerera kwemaerekitironi uye kugadzirwa kweATP, zvichikonzera kukuvara kwenhengo dzemuviri nekuda kwekushaya simba.
Mhedziso
Kusanganiswa kwemasero mumasero inzira inokosha inoshandisa kufambisa maerekitironi uye chemiosmosis kugadzira ATP, iyo inotakura simba guru mumasero. Kunzwisisa mashandiro ayo hakungokoshi chete kune biology yekutanga asiwo kunovhura mukana wekugadzira mishonga yezvirwere zvine chekuita nechirwere ichi chemetabolism. Kuramba uchiongorora mamorekuru e oxidative phosphorylation kuchabatsira vaongorori kuwana mhinduro itsva kumatambudziko ehutano hwevanhu.
