Ka Hana o Mitochondria i ke Kaʻina Hana o ka Hanu ʻana o ke Kelepona
Ua kapa pinepine ʻia ʻo Mitochondria ʻo ia nā "hale mana" o nā cell no ka mea hoʻopuka lākou i ka hapa nui o ka ikehu e pono ai no ke ola. Hoʻohana ʻia kēia ikehu no nā kaʻina hana like ʻole, mai ka ʻūlū ʻana o nā ʻiʻo a me ka lawe ʻana o nā mea ma waena o nā membrane a hiki i ka mahele ʻana o nā cell a me ka synthesis o nā molekala koʻikoʻi. Ma ke ʻano olaola, ʻo ka ikehu i hoʻohana pololei ʻia e nā cell ma ke ʻano o ATP (adenosine triphosphate). Hoʻopuka ʻia ka hapa nui o ATP ma o ka hanu ʻana o nā cell, a he kuleana koʻikoʻi ko ka mitochondria i kēia kaʻina hana.
ʻO ke ʻano Mitochondrial ma ke ʻano he hana kākoʻo
I mea e maopopo ai ka hana a ka mitochondria i ka hanu ʻana o ke kelepona, he mea nui e hoʻomaopopo i ko lākou ʻano kumu. ʻElua mau membrane o ka Mitochondria: kahi membrane waho permeable a me kahi membrane kūloko koho nui. Hoʻokumu ka membrane kūloko i nā pelu i kapa ʻia ʻo cristae. Hoʻonui kēia mau pelu i ka ʻili o ka membrane kūloko, e hāʻawi ana i kahi ākea no nā hopena hana ATP.
Aia i loko o ka membrane o loko ka matrix mitochondrial, kahi wai viscous e loaʻa ana nā enzymes koʻikoʻi, ka DNA mitochondrial, a me nā ribosomes. ʻO ke alo o ka DNA a me nā ribosomes e hōʻike ana he palena ko ka mitochondria i ka hiki ke hana i kekahi mau protein ma o lākou iho, ʻoiai ʻo ka hapa nui o kā lākou mau protein e hoʻopili ʻia nei e ka DNA nuklea o ke kelepona. ʻO ka hakahaka ma waena o nā membrane o waho a me loko ua kapa ʻia ʻo ka intermembrane space, kahi e pāʻani ai i kahi kuleana koʻikoʻi i ka hoʻokumu ʻana o ka gradient proton i ka wā hanu.
ʻAʻole wale kēia ʻano papa he ʻano, akā he hoʻolālā i kūpono loa no ka hoʻokō ʻana i ke kaʻina hana paʻakikī a me nā ʻanuʻu he nui o ka hanu ʻana o ke kelepona.
ʻIkepili o ka hanu ʻana o ke kelepona
ʻO ka hanu ʻana o ke kelepona he moʻo o nā hopena kemika e wāwahi i nā molekala meaʻai—ʻo ka glucose ka mea maʻamau—e hana i ka ATP. Hiki ke hoʻokaʻawale ʻia kēia kaʻina hana i kekahi mau pae nui: glycolysis, pyruvate oxidation, ka Krebs cycle (citric acid cycle), ke kaulahao lawe electron, a me ka oxidative phosphorylation. Ma waena o kēia mau pae, hana ʻia ka glycolysis ma ka cytoplasm, ʻoiai nā pae ma hope e hana ʻia ma ka mitochondria. I nā huaʻōlelo ʻē aʻe, ʻo mitochondria nā kikowaena nui o ka hana ikehu aerobic.
Ke Kūlana o Mitochondria Ma hope o Glycolysis
Hoʻopau ʻo Glycolysis i hoʻokahi mole glucose i ʻelua mau mole pyruvate, e hana ana i kahi liʻiliʻi o ATP a me NADH. Eia nō naʻe, ʻaʻole lawa ka ATP i hana ʻia e ka glycolysis wale nō e hoʻokō i nā pono ikehu o ka hapa nui o nā cell. ʻO kēia kahi e komo ai ka mitochondria.
Komo ka Pyruvate mai ka glycolysis i loko o ka mitochondria ma o nā protein halihali kūikawā i loko o ka membrane o loko. I loko o ka matrix, hana ka pyruvate i ka oxidation pyruvate (i kapa ʻia hoʻi ʻo ka bridging reaction) i Acetyl-CoA. Hoʻopuka kēia kaʻina hana iā NADH a hoʻokuʻu iā CO₂ ma ke ʻano he byproduct. ʻO Acetyl-CoA ka "tiketi komo" i ka pae aʻe, ʻo ke kaʻina hana Krebs.
Ka Pōʻaiapuni Krebs ma ka Mitochondrial Matrix
Hana ʻia ke kaʻina hana Krebs ma ka matrix mitochondrial a manaʻo e unuhi i ka ikehu hou aʻe mai ka acetyl-CoA. Ma kēia kaʻina hana, hui pū ka acetyl-CoA me ka oxaloacetate e hana i ka citrate, a laila e hana ʻia kekahi mau hopena enzymatic e hoʻi i ka oxaloacetate. I loko o kēia kaʻina hana, hoʻokuʻu ʻia ka CO₂ a hoʻokumu ʻia nā molekala lawe uila ikehu kiʻekiʻe e like me NADH a me FADH₂. Hoʻopuka pū ka kaʻina hana Krebs i nā liʻiliʻi o ATP (a i ʻole GTP, ma muli o ke ʻano o ke kelepona).
ʻOiai ʻo ke kaʻina hana Krebs e hoʻopuka i ka ATP, ʻo ka hāʻawi nui loa a ka mitochondria i ka ikehu o ke kelepona mai nā huahana NADH a me FADH₂. Lawe kēia mau molekala ʻelua i nā electrons ikehu kiʻekiʻe e hoʻohana ʻia i nā ʻanuʻu ma hope.
Kaula Hoʻoili Uila i loko o ka Membrane Loko o ka Mitochondrial
ʻO ka membrane mitochondrial o loko kahi o ke kaulahao lawe electron (ETC), kahi pūnaewele paʻakikī o nā protein a me nā molekala lawe electron. Hoʻoili ʻia nā electrons mai NADH a me FADH₂ mai kekahi paʻakikī a i kekahi. Hoʻokuʻu mālie kēia hoʻoili electron i ka ikehu, ma mua o ka manawa hoʻokahi, e ʻae ana i ka hoʻohana pono ʻana.
Hoʻohana ʻia ka ikehu i hoʻokuʻu ʻia e pamu i nā ion H⁺ (protons) mai ka matrix i loko o ka hakahaka intermembrane. Hoʻokumu kēia i kahi ʻokoʻa o ka nui o ka proton a me kahi uku uila ma waena o ka matrix a me ka hakahaka intermembrane. Ua kapa ʻia kēia ʻokoʻa ʻo ka electrochemical gradient a i ʻole ka proton motive force. Hōʻike kēia gradient i ka "ikaika hiki" a laila hoʻohana ʻia e hana i nā nui o ATP.
I ka hopena o ke kaulahao lawe uila, ua ʻae hope ʻia nā uila e ka oxygen (O₂) a hui pū me nā protons e hana i ka wai (H₂O). ʻO ia ke kumu he mea nui ka oxygen i ka hanu aerobic: me ka ʻole o ka oxygen ma ke ʻano he mea ʻae uila hope loa, e pau ke kaulahao lawe uila, a e emi nui ka hana ʻana o ATP.
ʻO ATP Synthase a me ka Oxidative Phosphorylation
He enzyme nui ka ATP synthase i hoʻokomo ʻia i loko o ka membrane mitochondrial o loko. Hana kēia enzyme e like me ka turbine molecular. Ke kahe hou nei nā protons mai ka intermembrane space i ka matrix ma o ATP synthase, hoʻohana ʻia ka ikehu o ke kahe proton e hoʻohui i ka ADP a me ka inorganic phosphate (Pi) e hana i ka ATP. ʻO kēia kaʻina hana hoʻokumu ATP, i hoʻokele ʻia e ka NADH/FADH₂ oxidation a me ke kahe proton, ua kapa ʻia ʻo oxidative phosphorylation.
Hāʻawi ka phosphorylation oxidative i ka hapa nui o ka ATP i ka hanu ʻana o ke kelepona aerobic. Ma keʻano laulā, hiki i hoʻokahi mole glucose ke hana ma kahi o 30-32 ATP (ʻokoʻa kēia helu ma muli o nā kūlana o ke kelepona a me ke ʻano o ka "shuttle" e lawe ana i ka cytoplasmic NADH i ka mitochondria). No kēia, ʻo ka hapa nui loa mai ka hana o ke kaulahao lawe electron a me ka ATP synthase i loko o ka mitochondria.
No ke aha he mea nui ʻo Krista?
ʻO nā Cristae nā ʻāpana o ka membrane o loko e hoʻonui ana i ka ʻili kahi e hana ai ke kaulahao lawe uila a me ka ATP synthase. ʻO ka nui o nā cristae, ʻo ka nui o ka ʻili no nā hopena hana ATP. ʻO ia ke kumu he nui nā mitochondria a me nā cristae i hoʻomohala nui ʻia i nā cell me nā koi ikehu kiʻekiʻe - e like me nā cell muscle cardiac. Hōʻike kēia ʻano i ka pilina pololei ma waena o nā pono ikehu o kahi cell a me ka hiki o ka mitochondria ke hana i ka ATP.
ʻO Mitochondria a me ka hoʻoponopono ʻana o ka metabolism ikehu
Ma waho aʻe o ka hana ʻana i ka ATP, he kuleana ko ka mitochondria i ka hoʻoponopono ʻana i ka metabolism o ke kelepona. Hiki i ka Mitochondria ke hoʻololi i ko lākou hanu ʻana e like me nā pono ikehu. Ke koi nā cell i ka ikehu hou aʻe, piʻi ka nui o ka hoʻohana ʻana i ka ATP, piʻi ka hana ʻana o ADP, a hoʻolalelale ʻia ka phosphorylation oxidative. I ka ʻaoʻao ʻē aʻe, inā emi ka pono o ka ikehu, emi pū ka nui o ka hanu ʻana. No laila, ʻaʻole wale ka mitochondria e "hana" i ka ikehu akā kōkua pū kekahi i ka mālama ʻana i ke kaulike ikehu o ke kelepona.
Ka hopena o nā maʻi hana Mitochondrial
Inā pilikia ka hana mitochondrial, ua emi ka hana ʻana o ATP a hiki i nā cell ke ʻike i ke kaumaha o ka ikehu. Ma lalo o kekahi mau kūlana, hiki i ka mitochondria ke hana i nā radical manuahi (ROS) ma ke ʻano he huahana o ke kaulahao lawe electron. I nā nui i kāohi ʻia, hiki i ka ROS ke pāʻani i kahi kuleana i ka hōʻailona cell, akā i ka nui, hiki iā lākou ke hōʻino i nā protein, lipids, a me ka DNA. Hoʻopili pinepine ʻia ka hōʻino ʻana o ka Mitochondrial i nā maʻi olakino like ʻole a me ka ʻelemakule , ʻoiai ke kūkākūkā ʻana ma mua o ka hanu ʻana o ke kelepona.
Ka hopena
He kuleana koʻikoʻi ko Mitochondria i ka hanu ʻana o ke kelepona aerobic ma o ka hoʻokō ʻana i nā ʻanuʻu koʻikoʻi ma hope o ka glycolysis, ʻoiai ka oxidation pyruvate, ke kaʻina hana Krebs, ke kaulahao lawe electron, a me ka phosphorylation oxidative. ʻO ke ʻano kū hoʻokahi o mitochondria—me kona membrane i pelu ʻia i loko e hana ana i ka cristae, matrix, a me ka intermembrane space—kākoʻo i ka hana ATP kūpono ma o ka hoʻokumu ʻana o kahi gradient proton a me ka hana o ATP synthase. Ma o kēia mau kaʻina hana, hāʻawi ka mitochondria i ka ikehu e pono ai no ke kelepona e hoʻokō i nā hana ola . No laila, ʻo ka hoʻomaopopo ʻana i ka hana o mitochondria i ka hanu ʻana o ke kelepona ʻo ia hoʻi ka hoʻomaopopo ʻana i kekahi o nā ʻano hana koʻikoʻi o ke ola ma ka pae kelepona.
