Imishini yamaselula

Ngo-2016, uMklomelo KaNobel kuKhemistry waklonyeliswa ngepumelelo emangazayo - ukuhlanganiswa kwama-molecule asebenza njengemishini eyimishini. Kodwa-ke, akunakushiwo ukuthi umqondo wokudala imishini emincane ungumbono womuntu wokuqala. Futhi kulokhu imvelo yayiqala.

Imishini yamangqamuzana eklonyelisiwe (okuningi mayelana nayo esihlokweni esiphuma kumagazini kaJanuwari we-MT) iyisinyathelo sokuqala esiya kubuchwepheshe obusha obungase buguqule izimpilo zethu phansi. Kodwa imizimba yazo zonke izinto eziphilayo igcwele izinqubo ze-nanoscale ezigcina amangqamuzana esebenza kahle.

Phakathi nendawo...

... amaseli aqukethe i-nucleus, futhi ulwazi lwezakhi zofuzo lugcinwa kuyo (amabhaktheriya awanayo i-nucleus ehlukile). I-molecule ye-DNA ngokwayo iyamangalisa - iqukethe izakhi ezingaphezu kwezigidi eziyizinkulungwane ezingu-6 (ama-nucleotides: isisekelo se-nitrogenous + ushukela we-deoxyribose + insalela ye-phosphoric acid), yakha imicu enengqikithi yobude obungamamitha angu-2. Futhi asibona ompetha kulokhu, ngoba kukhona izinto eziphilayo ezine-DNA ehlanganisa amakhulu ezinkulungwane zezigidi zama-nucleotide. Ukuze i-molecule enkulu kangaka ingene kuyi-nucleus, engabonakali ngeso lenyama, imicu ye-DNA isonteka ndawonye ibe i-helix (i-double helix) futhi isongwe amaprotheni akhethekile abizwa ngokuthi ama-histones. Iseli linesethi ekhethekile yemishini yokusebenza nale database.

Kumelwe usebenzise njalo ulwazi oluqukethwe ku-DNA: funda ukulandelana kwekhodi yamaprotheni owadingayo njengamanje (okulotshiweyo), futhi ukopishe yonke imininingwane egciniwe ngezikhathi ezithile ukuze uhlukanise iseli (ukuphindaphinda). Ngasinye salezi zinyathelo sihilela ukwembula i-helix yama-nucleotide. Kulo msebenzi, kusetshenziswa i-enzyme ye-helicase, ehamba ngokuzungeza futhi - njenge-wedge - ihlukanise ibe imicu ehlukene (konke lokhu kufana nombani). I-enzyme isebenza ngenxa yamandla akhishwe ngenxa yokuwohloka komthwali wamandla wendawo yonke weseli - i-ATP (adenosine triphosphate).

Imodeli ye-ATP molecule. Okunamathiselwe kanye nokwahlukaniswa kwezinsalela ze-phosphate (kwesokunxele) kunikeza ukushintshana kwamandla ngokusabela kwamakhemikhali eselula.

Manje ungaqala ukukopisha izingcezu zeketango, okwenziwa yi-RNA polymerase, futhi eqhutshwa amandla aqukethwe ku-ATP. I-enzyme ihamba ochungechungeni lwe-DNA futhi yakhe isifunda se-RNA (equkethe ushukela, i-ribose esikhundleni se-deoxyribose), okuyisifanekiso okwenziwa kuso amaprotheni. Ngenxa yalokho, i-DNA iyagcinwa (ukugwema ukuqaqa njalo nokufunda izingcezu), futhi, ngaphezu kwalokho, amaprotheni angadalwa kulo lonke ingqamuzana, hhayi nje ku-nucleus.

Ikhophi ecishe ibe namaphutha inikezwa i-DNA polymerase, esebenza ngendlela efanayo ne-RNA polymerase. I-enzayimu ihamba ngochungechunge futhi yakha umlingani wayo. Lapho enye i- molecule yale enzyme ihamba emugqeni wesibili, umphumela uba imicu emibili ephelele ye-DNA. I-enzyme idinga "abasizi" abambalwa ukuze iqale ukukopisha, ukubopha izingcezu ndawonye, ​​nokukhipha ama-stretch marks angadingekile. Kodwa-ke, i-DNA polymerase "inesici sokukhiqiza". Ingakwazi ukuya ohlangothini olulodwa kuphela. Ukuphindaphinda kudinga ukwakhiwa kwalokho okubizwa ngokuthi isiqalisi, lapho ukukopisha kwangempela kuqala khona. Uma sekuqediwe, ama-primers ayasuswa futhi, njengoba i-polymerase ingenayo ikhophi yasenqolobaneni, ifinyeza ngekhophi ngayinye ye-DNA. Emaphethelweni alolu chungechunge kukhona izingcezu ezivikelayo ezibizwa ngokuthi ama-telomere ezingawafaki ikhodi noma imaphi amaprotheni. Ngemva kokusetshenziswa kwawo (ebantwini, ngemva kokuphindaphinda okungaba ngu-50), ama-chromosome anamathelana futhi afundwa namaphutha, abangela ukufa kwamangqamuzana noma ukuguqulwa kwawo abe umdlavuza. Ngakho, isikhathi sokuphila kwethu silinganiswa ngewashi le-telomeric.

Ukukopisha i-DNA kudinga ama-enzyme amaningi ukuze asebenze ndawonye.

I-molecule elingana ne-DNA yenza umonakalo unomphela. Elinye iqembu lama-enzyme, elisebenza njengemishini ekhethekile, libhekene nokuxazulula izinkinga. Incazelo yendima yabo yaklonyeliswa ngoMklomelo Wekhemistry ka-2015 (ukuthola ulwazi olwengeziwe bheka isihloko sikaJanuwari 2016).

Ngaphakathi...

… amaseli ane-cytoplasm - ukumiswa kwezingxenye eziwagcwalisa ngemisebenzi ehlukahlukene ebalulekile. I-cytoplasm yonke imbozwe inethiwekhi yezakhiwo zamaprotheni ezakha i-cytoskeleton. Ama-microfibers anenkontileka avumela iseli ukuthi lishintshe ukuma kwalo, liyivumela ukuthi ikhase futhi inyakaze ama-organelles ayo angaphakathi. I-cytoskeleton ihlanganisa ne-microtubules, i.e. amashubhu enziwe ngamaprotheni. Lezi izakhi eziqinile ngokwanele (ishubhu elingenalutho lihlala liqinile kunenduku eyodwa yobubanzi obufanayo) akha iseli, futhi eminye yemishini yamangqamuzana engavamile kakhulu ihamba eduze kwayo - amaprotheni ahambayo (ngokoqobo!).

Ama-Microtubules aneziphetho ezishajwa ngogesi. Amaprotheni abizwa ngokuthi ama-dynein ahamba abheke engxenyeni engalungile, kuyilapho ama-kinesins ehamba ngendlela ehlukile. Ngenxa yamandla akhishwe ekuqhekekeni kwe-ATP, ukwakheka kwamaprotheni ahambayo (okubuye kwaziwe ngokuthi amaphrotheni ezimoto noma ezokuthutha) kuyashintsha emijikelezweni, okuwavumela ukuthi ahambe njengedada phezu kwama-microtubules. Ama-molecule afakwe "intambo" yephrotheni, kuze kube sekupheleni lapho enye i-molecule enkulu noma i-bubble egcwele imikhiqizo yemfucuza inganamathela. Konke lokhu kufana nerobhothi, elithi, linyakaza, lidonse ibhaluni ngentambo. Amaprotheni aginqikayo athutha izinto ezidingekayo ezindaweni ezifanele kuseli futhi ahambise izingxenye zawo zangaphakathi.

Cishe konke ukusabela okwenzeka engqamuzaneni kulawulwa ama-enzyme, ngaphandle kwalokho lezi zinguquko cishe bezingeke zenzeke. Ama-Enzymes ama-catalyst asebenza njengemishini ekhethekile ukwenza into eyodwa (imvamisa asheshisa ukusabela okuthile okuthile). Bathwebula ama-substrates okuguqulwa, bawahlele ngendlela efanele komunye nomunye, futhi ngemva kokuphela kwenqubo bakhulula imikhiqizo bese beqala ukusebenza futhi. Ukuhlotshaniswa nerobhothi lezimboni elenza izenzo eziphindaphindayo kuyiqiniso impela.

Ama-molecule we-intracellular energy carrier akhiwa njengomkhiqizo wochungechunge lokusabela kwamakhemikhali. Kodwa-ke, umthombo oyinhloko we-ATP wumsebenzi womshini oyinkimbinkimbi kakhulu weseli - i-ATP synthase. Inombolo enkulu yama-molecule ale enzyme itholakala ku-mitochondria, esebenza njenge "izitshalo zamandla" zamaselula.

I-ATP synthase - phezulu: ingxenye engashintshi

kulwelwesi, i-drive shaft, i-fragment enomthwalo wemfanelo

ukuze kuhlanganiswe i-ATP

Enqubweni ye-oxidation yezinto eziphilayo, ama-ion e-hydrogen ahanjiswa ngaphakathi kwezingxenye ngazinye ze-mitochondria ukuya ngaphandle, okudala ukuhleleka kwawo (umehluko wokugxila) kuzo zombili izinhlangothi zolwelwesi lwe-mitochondrial. Lesi simo asizinzile futhi kunokuthambekela okungokwemvelo kokugxila ukuze kulingane, okuyilokho i-ATP synthase esiza ngayo. I-enzyme iqukethe izingxenye eziningana ezihambayo nezigxilile. Ucezu olunamashaneli lugxilile kulwelwesi, lapho ama-ion e-hydrogen avela emvelweni angangena ku-mitochondria. Izinguquko zesakhiwo ezibangelwa ukunyakaza kwazo zizungeza enye ingxenye ye-enzyme - isakhi esinwetshiwe esisebenza njenge-drive shaft. Ngakolunye uhlangothi lwenduku, ngaphakathi kwe-mitochondria, enye ingxenye yesistimu ifakwe kuyo. Ukujikeleza kwe-shaft kubangela ukujikeleza kwengcezu yangaphakathi, lapho, kwezinye izikhundla zayo, ama-substrates e-ATP-forming reaction anamathiselwe, bese, kwezinye izikhundla ze-rotor, i-compound eyenziwe ngomumo eyenziwe yamandla aphezulu. . khululiwe.

Futhi kulokhu akunzima ukuthola isifaniso emhlabeni wobuchwepheshe bomuntu. Ijeneretha kagesi nje. Ukugeleza kwama-ion e-hydrogen kwenza izakhi zihambe ngaphakathi kwe-molecular motor enganyakazi kulwelwesi, njengama-blades e-turbine eqhutshwa umfudlana womusi wamanzi. I-shaft idlulisela idrayivu kusistimu yokukhiqiza ye-ATP yangempela. Njengama-enzyme amaningi, i-synthase nayo ingasebenza ngakolunye uhlangothi futhi iphule i-ATP. Le nqubo iqalisa ukunyakaza kwenjini yangaphakathi eshayela izingxenye ezihambayo zocezu lolwelwesi ku-shaft. Lokhu, futhi, kuholela ekumpompeni ama-ion e-hydrogen asuka ku-mitochondria. Ngakho, iphampu iqhutshwa ngogesi. Isimangaliso samangqamuzana emvelo.

Emngceleni...

... Phakathi kweseli nendawo ezungezile kukhona ulwelwesi lwamaseli oluhlukanisa ukuhleleka kwangaphakathi nesiphithiphithi sezwe langaphandle. Iqukethe ungqimba oluphindwe kabili lwama-molecule, nezingxenye ze-hydrophilic ("ezithanda amanzi") ngaphandle kanye nezingxenye ze-hydrophobic ("ezigwema amanzi") zibheke kwenye. Ulwelwesi luqukethe nama- molecule amaningi amaprotheni. Umzimba kufanele uthintane nendawo ezungezile: umunce izinto ozidingayo futhi ukhiphe udoti. Ezinye izinhlanganisela zamakhemikhali ezinama-molecule amancane (isibonelo, amanzi) zingadlula kulwelwesi kuzo zombili izinkomba ngokuya ngegradient yokuhlushwa. Ukusatshalaliswa kwabanye kunzima, futhi iseli ngokwalo lilawula ukumuncwa kwazo. Ngaphezu kwalokho, imishini yamaselula isetshenziselwa ukudlulisa - ama-conveyors namashaneli e-ion.

I-conveyor ibopha i-ion noma i-molecule bese ihamba nayo iye kolunye uhlangothi lwe-membrane (lapho ulwelwesi ngokwalo luncane) noma - lapho ludlula kulo lonke ulwelwesi - luhambisa inhlayiya eqoqiwe futhi iyikhulule ngakolunye uhlangothi. Yiqiniso, ama-conveyor asebenza ngazo zombili izindlela futhi "aphelele" kakhulu - avame ukuthutha uhlobo olulodwa lwento. Iziteshi ze-ion zibonisa umphumela ofanayo wokusebenza, kodwa indlela ehlukile. Zingafaniswa nesihlungi. Ukuthutha ngamashaneli e-ion ngokuvamile kulandela i-concentration gradient (okugxila phezulu kuya kwephansi kwe-ion kuze kube yilapho isuka ileveli). Ngakolunye uhlangothi, izindlela ze-intracellular zilawula ukuvulwa nokuvalwa kwamavesi. Iziteshi ze-ion futhi zibonisa ukukhetha okuphezulu ukuze izinhlayiya zidlule.

Isiteshi se-ion (kwesokunxele) namapayipi ayasebenza

I-flagellum yebhaktheriya iyindlela yokushayela yangempela

Kukhona omunye umshini wamangqamuzana othakazelisayo kulwelwesi lweseli - i-flagellum drive, eqinisekisa ukunyakaza okusebenzayo kwamabhaktheriya. Lena injini yamaprotheni ehlanganisa izingxenye ezimbili: ingxenye engashintshi (stator) nengxenye ejikelezayo (rotor). Ukunyakaza kubangelwa ukugeleza kwama-ion e-hydrogen kusuka kulwelwesi kuya engqamuzaneni. Bangena esiteshini ku-stator futhi baqhubekele engxenyeni ekude, etholakala ku-rotor. Ukuze ungene ngaphakathi kwengqamuzana, ama-ion e-hydrogen kufanele athole indlela eya esigabeni esilandelayo somzila, esiphinde sibe ku-stator. Kodwa-ke, i-rotor kufanele ijikeleze ukuze iziteshi zihlangane. Ukuphela kwe-rotor, ephumela ngaphesheya kwekheji, igobile, i-flagellum eguquguqukayo inamathele kuyo, ijikeleza njengophephela wendiza enophephela emhlane.

Ngikholwa ukuthi lokhu kubukezwa okufushane kwendlela yeselula kuzokucacisa ukuthi imiklamo ewinayo yabawine uMklomelo KaNobel, ngaphandle kokuchezukisa impumelelo yabo, isekude nokuphelela kokudalwa kokuziphendukela kwemvelo.