Michina yesero

Muna 2016, Mubairo weNobel muChemistry wakapihwa budiriro inokatyamadza - kuumbwa kwemamorekuru anoita semichina yemidziyo. Nekudaro, hazvigone kutaurwa kuti iyo pfungwa yekugadzira miniature muchina ipfungwa yekutanga yemunhu. Uye panguva ino zvisikwa zvaive zvekutanga.

Iwo akapihwa mamorekuru muchina (zvimwe nezvawo muchinyorwa kubva muna Ndira chinyorwa cheMT) inhanho yekutanga kuenda kuhunyanzvi hutsva hunogona kukurumidza kushandura hupenyu hwedu pasi. Asi miviri yezvipenyu zvose yakazara nenanoscale mechanisms inoita kuti masero arambe achishanda zvakanaka.

Pakati…

... masero ane nucleus, uye ruzivo rwemajini rwakachengetwa mairi (mabhakitiriya haana nucleus yakasiyana). Iyo DNA molecule pachayo inoshamisa - ine zvinhu zvinodarika mabhiriyoni matanhatu (nucleotides: nitrogenous base + deoxyribose sugar + phosphoric acid residue), ichiita shinda dzine hurefu hunosvika mamita maviri. Uye isu hatisi shasha panyaya iyi, nekuti kune zvipenyu zvine DNA ine mazana emabhiriyoni emanucleotides. Kuti gofori guru rakadaro rikwane mugotsi, risingaonekwe nemaziso, tambo dzeDNA dzinomonereka pamwe chete kuita helix (double helix) uye dzinoputirwa nemapuroteni akakosha anonzi histones. Sero rine seti yakakosha yemichina yekushanda neiyi dhatabhesi.

Iwe unofanirwa kugara uchishandisa ruzivo rwuri muDNA: verenga kutevedzana kwekodhi yemapuroteni auri kuda izvozvi (kunyorwa), uye kukopa dhatabhesi rese nguva nenguva kuti upatsanure sero (kudzokorora). Imwe neimwe yematanho aya inosanganisira kuburitsa helix yemanucleotides. Pachiitiko ichi, helicase enzyme inoshandiswa, inofamba mumhepo uye - seweji - inokamura kuita tambo dzakasiyana (zvese izvi zvakafanana nemheni). Iyo enzyme inoshanda nekuda kwesimba rinoburitswa semhedzisiro yekuparara kwepasi rose simba rinotakura sero - ATP (adenosine triphosphate).

Muenzaniso weATP molecule. Inonamirwa uye dhizaini yemafosfate residues (kuruboshwe) inopa shanduko yesimba mumaserura kemikari maitiro.

Iye zvino unogona kutanga kukopa cheni zvimedu, izvo RNA polymerase inoita, zvakare inofambiswa nesimba riri muATP. Iyo enzyme inofamba ichitevedza tambo yeDNA uye inoita nharaunda yeRNA (ine shuga, ribose pachinzvimbo che deoxyribose), inova template inogadzirwa mapuroteni. Nekuda kweizvozvo, DNA inochengetedzwa (kudzivisa kuramba kubheuka uye kuverenga zvimedu), uye, nekuwedzera, mapuroteni anogona kugadzirwa mukati mesero, kwete mumukati chete.

Iyo inenge isina kukanganisa kopi inopihwa neDNA polymerase, inoita zvakafanana neRNA polymerase. Iyo enzyme inofamba neshinda uye inovaka imwe yayo. Apo rimwe morekuru reiyi enzyme parinofamba richitevedza tambo yechipiri, mugumisiro wacho ndiwo tambo mbiri dzakakwana dzeDNA. Iyo enzyme inoda "vabatsiri" vashoma kuti vatange kukopa, kusungira zvimedu pamwechete, uye kubvisa mavanga asina kufanira. Nekudaro, DNA polymerase ine "chirema chekugadzira". Inogona chete kufamba munzira imwe. Kudzokorodza kunoda kusikwa kweanonzi anotanga, kubva panotanga kukopa chaiko. Kana yapera, maprimers anobviswa uye, sezvo polymerase isina backup, inopfupika nekopi yega yega yeDNA. Kumicheto kweshinda kune zvidimbu zvinodzivirira zvinonzi telomeres zvisingakodhe chero mapuroteni. Mushure mekushandisa kwavo (muvanhu, mushure mekudzokorora kanenge makumi mashanu), machromosome anonamatira pamwe chete uye anoverengwa nekukanganisa, izvo zvinokonzeresa kufa kwesero kana kushandurwa kwayo kuita kenza. Saka, nguva yehupenyu hwedu inoyerwa newachi yetelomeric.

Kukopa DNA kunoda maenzayimu akawanda kuti ashande pamwe chete.

A DNA-size molecule inokuvadzwa zvachose. Rimwe boka rema enzymes, rinoshanda semichina akasarudzika, rinobata nekugadzirisa matambudziko. Tsananguro yebasa ravo yakapihwa 2015 Chemistry Prize (kuti uwane rumwe ruzivo ona chinyorwa chaNdira 2016).

Mukati...

… masero ane cytoplasm - kuturika kwezvikamu zvinoazadza nemabasa akasiyana akakosha. Iyo yese cytoplasm yakafukidzwa ne network yeprotein zvimiro zvinoumba cytoskeleton. Iyo microfibers inobvumirana inobvumira sero kuti ichinje chimiro chayo, ichibvumira kukambaira uye kufambisa organelles yaro yemukati. Iyo cytoskeleton inosanganisirawo microtubules, i.e. machubhu akagadzirwa nemapuroteni. Izvi zvinhu zvakaomarara (hollow chubhu inogara yakaoma kupfuura tsvimbo imwe yedhayamita imwe chete) inoumba sero, uye mamwe emagetsi asina kujairika anofamba paari - kufamba mapuroteni (chaizvo!).

Microtubules ane magetsi anochajiswa magumo. Mapuroteni anonzi dyneins anofamba akananga kune iyo yakaipa fragment, nepo kinesins inofamba ichienda kune yakapesana. Nekuda kwesimba rakaburitswa kubva mukuputsika kweATP, chimiro chekufamba mapuroteni (anozivikanwawo semota kana mapuroteni ekutakura) anochinja mumatenderedza, achivabvumira kufamba sedhadha pamusoro pepamusoro pe microtubules. Mamolekyulu akashongedzerwa neprotein "shinda", kusvika kumagumo ayo mamwe mamorekuru makuru kana bubble rakazadzwa nemarara rinogona kunamatira. Zvose izvi zvakafanana nerobhoti, iyo, ichizununguka, inokwevera bharumu netambo. Mapuroteni anokunguruka anotakura zvinhu zvinodiwa kunzvimbo dzakakodzera musero uye kufambisa zvikamu zvaro zvemukati.

Kunenge kuita kwese kunoitika musero kunodzorwa nema enzymes, pasina izvo shanduko idzi dzaisazomboitika. MaEnzymes anokonzeresa anoita semichina akasarudzika kuita chinhu chimwe (kazhinji anongomhanyisa imwe chete maitiro). Vanotora ma substrates ekushandura, varongedze zvakakodzera kune mumwe nemumwe, uye mushure mekupera kwemaitiro vanosunungura zvigadzirwa uye votanga kushanda zvakare. Kushamwaridzana nerobhoti reindasitiri rinoita kudzokorora zviito zvisingaperi ndezvechokwadi.

Mamolekyulu eiyo intracellular energy carrier anoumbwa senge-chigadzirwa cheakatevedzana emakemikari reactions. Nekudaro, iyo huru sosi yeATP ibasa reiyo yakaomesesa meshini yesero - ATP synthase. Huwandu hukuru hwemamorekuru eiyi enzyme inowanikwa mumitochondria, inoshanda semaserura "simba rezvirimwa".

ATP synthase - pamusoro: yakagadziriswa chikamu

mu membrane, drive shaft, chidimbu chine mutoro

yeATP synthesis

Mukuita kwebiological oxidation, maion ehydrogen anotakurwa kubva mukati mechikamu chimwe nechimwe chemitochondria kuenda kunze, izvo zvinogadzira gradient yavo (concentration difference) kumativi ese emitochondrial membrane. Mamiriro ezvinhu aya haana kugadzikana uye kune tsika yechisikigo yekutarisisa kuenzana, izvo zvinotora mukana weATP synthase. Iyo enzyme ine akati wandei anofamba uye akagadziriswa zvikamu. Chimedu chine machani chinomisikidzwa mu membrane, kuburikidza iyo hydrogen ions kubva kunharaunda inogona kupinda mumitochondria. Kuchinja kwemaitiro kunokonzerwa nekufamba kwavo kunotenderera chimwe chikamu che enzyme - chinhu chakareba chinoita sedhiraivha. Kune rumwe rutivi rwetsvimbo, mukati memitochondria, imwe chidimbu chegadziriro inosungirirwa pairi. Kutenderera kweshaft kunokonzera kutenderera kwechikamu chemukati, icho, mune dzimwe nzvimbo dzayo, substrates yeATP-forming reaction inosungirirwa, uyezve, mune dzimwe nzvimbo dze rotor, yakagadzirira-yakagadzirirwa-yakagadzirirwa simba guru. . kusunungurwa.

Uye panguva ino hazvisi zvakaoma kuwana kuenzanisa munyika ye teknolojia yevanhu. Ingori jenareta remagetsi. Kuyerera kwemaioni ehydrogen kunoita kuti zvinhu zvifambe mukati memotor motor isingafambe mu membrane, kunge mablades eturbine anofambiswa nerukova rwemhute yemvura. Iyo shaft inoendesa drive kune chaiyo ATP chizvarwa system. Kufanana nema enzymes mazhinji, synthase inogonawo kuita mune imwe nzira uye kuputsa ATP. Iyi nzira inomisa mota yemukati inotyaira zvikamu zvinofamba zvemembrane fragment kuburikidza neshaft. Izvi, zvakare, zvinotungamira mukupomba kunze kwehydrogen ion kubva kumitochondria. Saka, pombi inofambiswa nemagetsi. Molecular chishamiso chezvakasikwa.

Pabhodha…

... Pakati pesero uye zvakatipoteredza pane sero membrane inoparadzanisa kurongeka kwemukati kubva mumhirizhonga yenyika yekunze. Inoumbwa nekaviri layer yemamorekuru, ine hydrophilic ("inoda mvura") zvikamu zvekunze uye hydrophobic ("inodzivirira mvura") zvikamu zvakatarisana. Iyo membrane inewo akawanda mapuroteni mamorekuru. Muviri unofanirwa kusangana nenharaunda: tora zvinhu zvauri kuda uye kuburitsa tsvina. Mamwe makemikoro ane mamorekuru madiki (semuenzaniso, mvura) anogona kupfuura nemukati memembrane mumativi ese zvichienderana neconcentration gradient. Kupararira kwevamwe kwakaoma, uye sero pacharo rinoronga kutora kwavo. Kupfuurirazve, michina yemaserura inoshandiswa kutapurirana - conveyors uye ion chiteshi.

Mutakuri anosunga ayoni kana mamorekuru obva afamba nayo kune rimwe divi re membrane (apo membrane pachayo idiki) kana - kana ichipfuura nemu membrane yese - inofambisa chidimbu chakaunganidzwa ichichiregedza kune rumwe rutivi. Ehe, maconveyor anoshanda nenzira mbiri uye ane "finicky" - anowanzo takura mhando imwe chete yezvinhu. Ion nzira dzinoratidza kushanda kwakafanana, asi imwe nzira. Dzinogona kufananidzwa nesefa. Kutakura kuburikidza nema ion machani kazhinji kunoteedzera concentration gradient (yakakwirira kusvika yakaderera ion concentrations kusvika yadzika). Kune rumwe rutivi, intracellular mechanisms inodzora kuvhurwa nekuvhara kwendima. Iyo ion chiteshi inoratidzawo yakakwira selectivity kuti zvimedu zvipfuure.

Ion chiteshi (kuruboshwe) uye mapaipi ari kushanda

Iyo bhakitiriya flagellum inzira yechokwadi yekutyaira

Pane imwe inonakidza molecular muchina musero membrane - iyo flagellum drive, inova nechokwadi chekufamba kwebhakitiriya. Iyi ipuroteni injini ine zvikamu zviviri: chikamu chakagadziriswa (stator) uye chikamu chinotenderera (rotor). Movement inokonzerwa nekuyerera kwehydrogen ions kubva mu membrane kupinda musero. Vanopinda mugero mu stator uye vachiwedzera kupinda mukati me distal part, iyo iri mu rotor. Kuti upinde mukati mesero, maion ehydrogen anofanira kuwana nzira yekuenda kune chikamu chinotevera chegwara, iro zvakare mune stator. Nekudaro, iyo rotor inofanirwa kutenderera kuitira kuti migero isanganise. Magumo e rotor, achibuda kunze kwekeji, yakakotama; inochinjika flagellum inosungirirwa pairi, ichitenderera senge helicopter propeller.

Ini ndinotenda kuti izvi zvinongo pfupisa pamusoro peiyo cellular mechanism ichaita kuti zvive pachena kuti magadzirirwo anokunda evakahwina Mubairo weNobel, pasina kukanganisa zvavakawana, achiri kure nekukwana kwezvisikwa zvekushanduka-shanduka.