Injin salula

A shekara ta 2016, an ba da lambar yabo ta Nobel a fannin ilmin sinadarai don samun nasara mai ban sha'awa - haɗakar kwayoyin halitta waɗanda ke aiki a matsayin na'urori na inji. Duk da haka, ba za a iya cewa ra'ayin ƙirƙirar ƙananan injuna ra'ayin mutum ne na asali ba. Kuma wannan lokacin yanayi ya fara.

Injin kwayoyin da aka ba da lambar yabo (ƙari game da su a cikin labarin daga fitowar Janairu na MT) sune mataki na farko zuwa sabuwar fasaha da za ta iya juyar da rayuwarmu nan ba da jimawa ba. Amma jikkunan dukkan rayayyun halittu suna cike da sinadarai na nanoscale wadanda ke kiyaye sel suna aiki yadda ya kamata.

A tsakiya…

... Kwayoyin suna dauke da kwayar halitta, kuma ana adana bayanan kwayoyin halitta a cikinsa (kwayoyin cuta ba su da bambancin tsakiya). Kwayar halittar DNA da kanta tana da ban mamaki - ta ƙunshi abubuwa sama da biliyan 6 (nucleotides: tushen nitrogen + deoxyribose sugar + ragowar phosphoric acid), suna samar da zaren tare da jimlar kusan mita 2. Kuma mu ba zakara ba ne a wannan fanni, domin akwai kwayoyin halitta wadanda DNA ta kunshi daruruwan biliyoyin nucleotides. Domin irin wannan katuwar kwayoyin halitta ta shiga cikin tsakiya, wanda ido bai iya gani ba, sai a karkatar da igiyoyin DNA tare zuwa wani helix (helix biyu) kuma a nannade su da sunadaran sunadaran da ake kira histones. Tantanin halitta yana da na'urori na musamman don aiki tare da wannan bayanan.

Dole ne ku yi amfani da bayanan da ke cikin DNA koyaushe: karanta jerin jerin sunadaran sunadaran da kuke buƙata a halin yanzu (fassara), sannan kwafi duk bayanan bayanai daga lokaci zuwa lokaci don rarraba tantanin halitta (kwafi). Kowane ɗayan waɗannan matakan sun haɗa da buɗe helix na nucleotides. Don wannan aikin, ana amfani da enzyme na helicase, wanda ke motsawa a cikin karkace kuma - kamar kullun - ya raba shi zuwa zaren daban (duk wannan yana kama da walƙiya). Enzyme yana aiki ne saboda kuzarin da aka fitar a sakamakon rushewar mai ɗaukar makamashi na duniya - ATP (adenosine triphosphate).

Model na kwayoyin ATP. Haɗe-haɗe da rarrabuwa na phosphate (hagu) suna ba da musayar makamashi a cikin halayen sinadarai na salula.

Yanzu zaku iya fara kwafin ɓangarorin sarƙoƙi, waɗanda RNA polymerase ke yi, wanda kuma makamashin da ke cikin ATP ke motsa shi. Enzyme yana motsawa tare da madaidaicin DNA kuma ya samar da yanki na RNA (wanda ya ƙunshi sukari, ribose maimakon deoxyribose), wanda shine samfurin da aka haɗa sunadaran. A sakamakon haka, ana kiyaye DNA (kauce wa ci gaba da warwarewa da karanta guntu), kuma, ƙari, ana iya ƙirƙirar sunadarai a cikin tantanin halitta, ba kawai a cikin tsakiya ba.

Ana samar da kwafin kusan babu kuskure ta hanyar DNA polymerase, wanda ke aiki daidai da RNA polymerase. Enzyme yana motsawa tare da zaren kuma yana gina takwaransa. Lokacin da wani kwayoyin halitta na wannan enzyme ya motsa tare da igiya na biyu, sakamakon shine cikakken nau'i biyu na DNA. Enzyme yana buƙatar ƴan “masu taimako” don fara kwafi, ɗaure gutsuttsura tare, da cire alamun shimfiɗa maras buƙata. Duk da haka, DNA polymerase yana da "laikan masana'antu". Yana iya motsawa ta hanya daya kawai. Maimaitawa yana buƙatar ƙirƙirar abin da ake kira Starter, daga inda ainihin kwafi zai fara. Da zarar an kammala, an cire abubuwan farko kuma, tun da polymerase ba shi da madadin, yana ragewa tare da kowane kwafin DNA. A ƙarshen zaren akwai guntu masu kariya da ake kira telomeres waɗanda ba su da lambar kowane sunadaran. Bayan cinye su (a cikin mutane, bayan kusan 50 maimaitawa), chromosomes suna manne tare kuma ana karanta su tare da kurakurai, wanda ke haifar da mutuwar kwayar halitta ko kuma canza shi zuwa wani ciwon daji. Don haka, ana auna lokacin rayuwarmu da agogon telomeric.

Kwafi DNA yana buƙatar enzymes da yawa don yin aiki tare.

Kwayar halitta mai girman DNA tana fuskantar lalacewa ta dindindin. Wani rukuni na enzymes, wanda kuma ke aiki a matsayin injuna na musamman, yana hulɗa da matsala. An ba da bayanin rawar da suka taka lambar yabo ta Chemistry na 2015 (don ƙarin bayani duba labarin Janairu 2016).

Ciki…

... Kwayoyin suna da cytoplasm - dakatarwar abubuwan da ke cika su da ayyuka masu mahimmanci daban-daban. Gabaɗayan cytoplasm an rufe shi da hanyar sadarwa na sifofin sunadaran da suka haɗa cytoskeleton. Microfibers masu kwangila suna ba da damar tantanin halitta ya canza siffarsa, yana ba shi damar yin rarrafe da motsa gabobin cikin ciki. Cytoskeleton kuma ya haɗa da microtubules, i.e. tubes sanya daga sunadarai. Wadannan abubuwa ne masu tsauri (bututu mai zurfi koyaushe yana da ƙarfi fiye da sanda guda ɗaya mai diamita ɗaya) waɗanda ke samar da tantanin halitta, kuma wasu na'urorin da ba a saba gani ba suna tafiya tare da su - sunadaran tafiya (a zahiri!).

Microtubules suna da iyakar cajin lantarki. Sunadaran da ake kira dyneins suna matsawa zuwa guntun da ba su da kyau, yayin da kinesin ke motsawa a kishiyar shugabanci. Godiya ga makamashin da aka saki daga rushewar ATP, siffar sunadaran tafiya (wanda aka sani da sunadaran mota ko sufuri) suna canzawa a cikin hawan keke, yana ba su damar motsawa kamar duck a fadin saman microtubules. Molecules suna sanye da furotin "zaren", har zuwa ƙarshensa wani babban kwayar halitta ko kumfa mai cike da kayan sharar gida na iya tsayawa. Duk wannan yayi kama da mutum-mutumi, wanda, yana karkata, yana jan balloon ta igiya. Sunadaran birgima suna ɗaukar abubuwan da ake buƙata zuwa wuraren da suka dace a cikin tantanin halitta kuma suna motsa abubuwan ciki.

Kusan duk halayen da ke faruwa a cikin tantanin halitta ana sarrafa su ta hanyar enzymes, wanda ba tare da wanda waɗannan canje-canjen ba zasu taɓa faruwa ba. Enzymes su ne masu kara kuzari waɗanda suke aiki kamar na'urori na musamman don yin abu ɗaya (sau da yawa suna saurin amsawa ɗaya kawai). Suna kama abubuwan canzawa, shirya su daidai da juna, kuma bayan ƙarshen tsari sun saki samfuran kuma su sake yin aiki. Haɗin kai tare da mutum-mutumin masana'antu yana aiwatar da ayyuka marasa iyaka gaskiya ne.

Molecules na mai ɗaukar makamashi na ciki suna samuwa azaman ta hanyar-samfurin jerin halayen sinadarai. Duk da haka, babban tushen ATP shine aikin mafi hadaddun tsarin kwayar halitta - ATP synthase. Mafi yawan adadin kwayoyin wannan enzyme yana cikin mitochondria, wanda ke aiki a matsayin "tsaran wutar lantarki".

ATP synthase - saman: tsayayyen sashi

a cikin membrane, tuƙi shaft, alhakin gutsuttsura

don haɗin ATP

A cikin aiwatar da iskar oxygenation na halitta, ana jigilar hydrogen ions daga ciki na kowane sassan mitochondria zuwa waje, wanda ke haifar da gradient (bambancin tattarawa) a bangarorin biyu na mitochondrial membrane. Wannan halin da ake ciki ba shi da tabbas kuma akwai yanayi na dabi'a don ƙaddamarwa don daidaitawa, wanda shine abin da ATP synthase ke amfani da shi. Enzyme ya ƙunshi sassa da yawa masu motsi da gyarawa. An gyara guntu tare da tashoshi a cikin membrane, ta hanyar da ions hydrogen daga yanayin zai iya shiga cikin mitochondria. Canje-canjen tsarin da motsinsu ya haifar yana jujjuya wani sashi na enzyme - wani abu mai elongated wanda ke aiki azaman tuƙi. A ɗayan ƙarshen sanda, a cikin mitochondion, wani yanki na tsarin yana haɗe da shi. Juyawa na shaft yana haifar da jujjuyawar guntun ciki, wanda - a cikin wasu matsayi - an haɗa abubuwan da ke haifar da amsawar ATP, sa'an nan kuma - a cikin sauran wurare na rotor - da aka gama babban makamashi mai ƙarfi. saki.

Kuma a wannan karon ba shi da wahala a sami kwatance a duniyar fasahar ɗan adam. Generator wuta kawai. Gudun ions na hydrogen yana sa abubuwan su motsa cikin motar kwayoyin da ba su iya motsi a cikin membrane, kamar ruwan wukake na injin turbin da kogin ruwa ke motsawa. Shaft yana canja wurin tuƙi zuwa ainihin tsarin tsara ATP. Kamar yawancin enzymes, synthase kuma na iya yin aiki a wata hanya kuma ya rushe ATP. Wannan tsari yana kunna motsin motsi na ciki wanda ke tafiyar da sassa masu motsi na guntun membrane ta rafi. Wannan, bi da bi, yana kaiwa ga fitar da ions hydrogen daga mitochondria. Don haka, famfon yana tuƙi ta hanyar lantarki. Mu'ujiza na kwayoyin halitta.

Zuwa kan iyakoki...

... Tsakanin tantanin halitta da muhalli akwai kwayar halitta wanda ke raba tsari na ciki da hargitsi na duniyar waje. Ya ƙunshi nau'i biyu na kwayoyin halitta, tare da sassan hydrophilic ("ƙaunar ruwa") a waje da sassan hydrophobic ("kaucewa ruwa") zuwa juna. Har ila yau, membrane ya ƙunshi ƙwayoyin furotin da yawa. Dole ne jiki ya haɗu da yanayin: sha abubuwan da yake buƙata kuma ya saki sharar gida. Wasu mahadi masu sinadarai tare da ƙananan ƙwayoyin cuta (misali, ruwa) na iya wucewa ta cikin membrane a cikin kwatance biyu bisa ga ƙaddamarwar taro. Yaduwa na wasu yana da wahala, kuma tantanin halitta da kansa yana daidaita sha. Bugu da ari, ana amfani da injunan salula don watsawa - masu jigilar kaya da tashoshi ion.

Mai ɗaukar ion ko molecule sannan ya motsa tare da shi zuwa wancan gefen membrane (lokacin da membrane da kansa ya yi ƙanƙanta) ko - idan ya ratsa ta gaba ɗaya membrane - yana motsa barbashin da aka tattara ya sake shi a ɗayan ƙarshen. Tabbas, masu jigilar kaya suna aiki duka hanyoyi biyu kuma suna da “ƙananan” - galibi suna jigilar nau'ikan abu ɗaya ne kawai. Tashoshin ion suna nuna irin tasirin aiki iri ɗaya, amma wata hanya dabam. Ana iya kwatanta su da tacewa. Sufuri ta tashoshi ion gabaɗaya yana biye da matakin maida hankali (mafi girma zuwa ƙananan matakan ion har sai sun daidaita). A daya bangaren kuma, hanyoyin cikin salula suna tsara budewa da rufe hanyoyin. Tashoshin ion kuma suna nuna babban zaɓi don barbashi don wucewa.

Ion tashar (hagu) da bututun da ke aiki

Tutar kwayan cuta hanya ce ta tuƙi ta gaske

Akwai wata na'ura mai ban sha'awa mai ban sha'awa a cikin kwayar halitta - motsi na flagellum, wanda ke tabbatar da motsi na kwayoyin cuta. Wannan injin gina jiki ne wanda ya ƙunshi sassa biyu: kafaffen sashi (stator) da juzu'i mai juyawa (rotor). Ana haifar da motsi ta hanyar kwararar ions hydrogen daga membrane zuwa cikin tantanin halitta. Suna shigar da tashar a cikin stator kuma suna kara zuwa ɓangaren nesa, wanda ke cikin rotor. Don shiga cikin tantanin halitta, ions hydrogen dole ne su sami hanyar zuwa sashe na gaba na tashar, wanda yake a cikin stator. Koyaya, rotor dole ne ya juya don tashoshi su haɗu. Ƙarshen na'ura mai juyi, yana fitowa bayan keji, yana lanƙwasa, an makala tuta mai sassauƙa da shi, yana jujjuyawa kamar jirgin sama mai saukar ungulu.

Na yi imanin cewa wannan taƙaitaccen taƙaitaccen bayani game da tsarin salula zai bayyana a fili cewa ƙirar da suka samu lambar yabo ta Nobel, ba tare da lahani daga nasarorin da suka samu ba, har yanzu suna da nisa daga kamala na abubuwan da aka halitta na juyin halitta.