Makina a cell

Mu 2016, Mphotho ya Nobel mu Chemistry idaperekedwa chifukwa chakuchita bwino - kaphatikizidwe ka mamolekyu omwe amakhala ngati zida zamakina. Komabe, sitinganene kuti lingaliro la kupanga makina ang'onoang'ono ndi lingaliro loyambirira laumunthu. Ndipo nthawi iyi chilengedwe chinali choyamba.

Makina amolekyu omwe adapatsidwa (zambiri za iwo m'nkhani yochokera mu Januwale MT) ndiye gawo loyamba lopita kuukadaulo watsopano womwe ukhoza kusintha miyoyo yathu posachedwa. Koma matupi a zamoyo zonse amakhala odzaza ndi ma nanoscale njira zomwe zimapangitsa kuti maselo azigwira ntchito bwino.

M'kati mwa…

... maselo ali ndi phata, ndipo zambiri za majini zimasungidwa mmenemo (mabakiteriya alibe phata lapadera). Molekyu ya DNA yokha ndiyodabwitsa - imakhala ndi zinthu zopitilira 6 biliyoni (nyukleotides: nitrogenous base + deoxyribose shuga + zotsalira za phosphoric acid), kupanga ulusi wokhala ndi kutalika pafupifupi 2 metres. Ndipo ife sitiri akatswiri pankhaniyi, chifukwa pali zamoyo zomwe DNA ili ndi mazana a mabiliyoni a nucleotides. Kuti molekyu ikuluikulu yotereyi igwirizane ndi phata, yosaoneka ndi maso, nsinga za DNA zimapindika pamodzi n’kukhala helix (double helix) n’kuzikulunga mozungulira mapuloteni apadera otchedwa histones. Selo ili ndi makina apadera ogwirira ntchito ndi databaseyi.

Muyenera kugwiritsa ntchito zomwe zili mu DNA nthawi zonse: werengani ma code a mapuloteni omwe mukufuna (zolemba), ndikukopera database yonse nthawi ndi nthawi kuti mugawane selo (kubwerezabwereza). Chilichonse mwa njirazi chimaphatikizapo kuvumbulutsa chigawo cha nucleotide. Pochita izi, enzyme ya helicase imagwiritsidwa ntchito, yomwe imayenda mozungulira ndipo - ngati mphero - imagawaniza ulusi wosiyana (zonsezi zikufanana ndi mphezi). Enzyme imagwira ntchito chifukwa cha mphamvu yotulutsidwa chifukwa cha kuwonongeka kwa chonyamulira champhamvu cha cell - ATP (adenosine triphosphate).

Chitsanzo cha molekyulu ya ATP. Kumangirizidwa ndi kuchotsedwa kwa zotsalira za phosphate (kumanzere) kumapereka kusinthana kwamphamvu pamachitidwe amankhwala am'manja.

Tsopano mutha kuyamba kukopera zidutswa zamaketani, zomwe RNA polymerase imachita, zomwe zimayendetsedwa ndi mphamvu zomwe zili mu ATP. Enzymeyi imayenda motsatira chingwe cha DNA ndikupanga chigawo cha RNA (chokhala ndi shuga, ribose mmalo mwa deoxyribose), chomwe ndi template yomwe mapuloteni amapangidwira. Chotsatira chake, DNA imasungidwa (kupewa kusasunthika kosalekeza ndi kuwerenga zidutswa), ndipo, kuwonjezera apo, mapuloteni amatha kupangidwa mu selo lonse, osati mu nucleus yokha.

Kope pafupifupi yopanda cholakwika imaperekedwa ndi DNA polymerase, yomwe imagwira ntchito mofanana ndi RNA polymerase. Enzyme imayenda motsatira ulusi ndikumanga mnzake. Molekyu ina ya enzyme imeneyi ikamayenda pa chingwe chachiwiri, pamakhala tizigawo tiwiri tathunthu ta DNA. Enzyme imafunikira "othandizira" angapo kuti ayambe kukopera, kumangirira zidutswa pamodzi, ndikuchotsa zipsera zosafunikira. Komabe, DNA polymerase ili ndi "chilema chopanga". Ikhoza kusuntha mbali imodzi yokha. Kubwereza kumafuna kupanga chotchedwa choyambira, pomwe kukopera kwenikweni kumayambira. Akamaliza, zoyambira zimachotsedwa ndipo, popeza polymerase ilibe zosunga zobwezeretsera, imafupikitsa ndi kopi iliyonse ya DNA. Kumapeto kwa ulusiwo kuli tizidutswa ta zoteteza zotchedwa ma telomeres zomwe sizilemba mapuloteni aliwonse. Atatha kumwa (mwa anthu, atatha kubwereza pafupifupi 50), ma chromosome amamatira pamodzi ndipo amawerengedwa ndi zolakwika, zomwe zimayambitsa kufa kwa selo kapena kusintha kwake kukhala khansa. Motero, nthawi ya moyo wathu imayesedwa ndi wotchi ya telomeric.

Kutengera DNA kumafuna michere yambiri kuti igwire ntchito limodzi.

Molekyu yamtundu wa DNA imawonongeka kosatha. Gulu lina la michere, lomwe limagwiranso ntchito ngati makina apadera, limalimbana ndi zovuta. Kufotokozera za udindo wawo adapatsidwa Mphotho ya Chemistry ya 2015 (kuti mumve zambiri onani nkhani ya Januware 2016).

Mkati…

… Maselo ali ndi cytoplasm - kuyimitsidwa kwa zigawo zomwe zimawadzaza ndi ntchito zosiyanasiyana zofunika. Cytoplasm yonse imakutidwa ndi gulu la mapuloteni omwe amapanga cytoskeleton. Ma microfibers omwe amalumikizana nawo amalola selo kusintha mawonekedwe ake, kulola kukwawa ndikusuntha ziwalo zake zamkati. Cytoskeleton imaphatikizaponso ma microtubules, i.e. machubu opangidwa ndi mapuloteni. Izi ndi zinthu zolimba (chubu chopanda kanthu nthawi zonse chimakhala cholimba kuposa ndodo imodzi yofanana) yomwe imapanga selo, ndipo makina ena achilendo kwambiri amayenda motsatira - mapuloteni oyenda (kwenikweni!).

Ma Microtubules ali ndi malekezero amagetsi. Mapuloteni otchedwa dyneins amasunthira ku chidutswa choyipa, pomwe kinesins amasunthira kwina. Chifukwa cha mphamvu yomwe imatulutsidwa kuchokera ku kuwonongeka kwa ATP, mawonekedwe a mapuloteni oyenda (omwe amadziwikanso kuti mapuloteni a galimoto kapena zoyendetsa) amasintha mozungulira, kuwalola kuyenda ngati bakha kudutsa pamwamba pa ma microtubules. Mamolekyulu ali ndi "ulusi" wa mapuloteni, mpaka kumapeto kwake komwe molekyu ina yayikulu kapena thovu lodzaza ndi zinyalala limatha kumamatira. Zonsezi zikufanana ndi robot, yomwe, ikugwedezeka, imakoka buluni ndi chingwe. Mapuloteni ogubuduza amanyamula zinthu zofunika kupita kumalo oyenera mu selo ndikusuntha zigawo zake zamkati.

Pafupifupi zochitika zonse zomwe zimachitika muselo zimayendetsedwa ndi michere, popanda zomwe kusinthaku sikungachitike. Ma enzymes ndi zinthu zomwe zimagwira ntchito ngati makina apadera kuti achite chinthu chimodzi (nthawi zambiri amangofulumira kuchitapo kanthu). Amagwira magawo osinthika, amawakonzekera moyenera kwa wina ndi mzake, ndipo pamapeto a ndondomekoyi amamasula zinthuzo ndikuyambanso kugwira ntchito. Kugwirizana ndi loboti yamakampani yomwe imachita zinthu zobwerezabwereza kosatha ndizoonadi.

Mamolekyulu a onyamula mphamvu ya okhudza maselo ambiri amapangidwa monga mwa-katundu wa mndandanda wa zimachitikira mankhwala. Komabe, gwero lalikulu la ATP ndi ntchito ya makina ovuta kwambiri a selo - ATP synthase. Mamolekyu ambiri a enzyme iyi ali mu mitochondria, yomwe imakhala ngati "zomera zamagetsi".

ATP synthase - pamwamba: gawo lokhazikika

mu nembanemba, drive kutsinde, udindo chidutswa

kwa ATP synthesis

M'kati mwa biological oxidation, ayoni wa haidrojeni amatengedwa kuchokera mkati mwa zigawo za mitochondria kupita kunja, zomwe zimapanga gradient (kusiyana kwa concentration) mbali zonse za nembanemba ya mitochondrial. Izi ndizosakhazikika ndipo pali chizolowezi chachilengedwe choti kukhazikika kufanane, zomwe ndizomwe ATP synthase imapezerapo mwayi. Enzyme imakhala ndi magawo angapo osuntha komanso osasunthika. Chidutswa chokhala ndi ngalande chimakhazikika mu nembanemba, momwe ma ayoni a haidrojeni ochokera ku chilengedwe amatha kulowa mu mitochondria. Zosintha zamapangidwe zomwe zimachitika chifukwa cha kayendetsedwe kawo zimazungulira gawo lina la puloteni - chinthu chotalikirana chomwe chimakhala ngati shaft yoyendetsa. Kumapeto ena a ndodo, mkati mwa mitochondrion, chidutswa china cha dongosolo chimamangiriridwa kwa icho. Kuzungulira kwa shaft kumayambitsa kusinthasintha kwa chidutswa chamkati, chomwe - m'malo ake ena - magawo a ATP-forming reaction amamangiriridwa, ndiyeno - m'malo ena a rotor - chomaliza champhamvu champhamvu. kumasulidwa.

Ndipo nthawi ino sizovuta kupeza fanizo mu dziko la teknoloji yaumunthu. Jenereta yamagetsi basi. Kuyenda kwa ayoni wa haidrojeni kumapangitsa kuti zinthu ziziyenda mkati mwa mamolekyu osasunthika mu nembanemba, ngati masamba a turbine oyendetsedwa ndi mtsinje wa nthunzi wamadzi. Shaft imasamutsa galimotoyo ku dongosolo lenileni la ATP. Monga ma enzymes ambiri, synthase imatha kuchitanso mbali ina ndikuphwanya ATP. Izi zimachititsa kuti injini yamkati iyambe kuyendetsa mbali zosuntha za kachidutswa ka membrane. Izi, nazonso, zimabweretsa kutulutsa ma ayoni a haidrojeni kuchokera ku mitochondria. Choncho, pampu imayendetsedwa ndi magetsi. Molecular chozizwitsa cha chilengedwe.

Ku malire...

... Pakati pa selo ndi chilengedwe pali nembanemba ya selo yomwe imalekanitsa dongosolo lamkati ndi chisokonezo cha dziko lakunja. Amakhala ndi magawo awiri a mamolekyu, okhala ndi mbali za hydrophilic ("zokonda madzi") zakunja ndi za hydrophobic ("kupewa madzi") kwa wina ndi mnzake. Nembanembayo ilinso ndi mamolekyu ambiri a mapuloteni. Thupi liyenera kukhudzana ndi chilengedwe: kutenga zinthu zomwe likufunikira ndikutulutsa zinyalala. Mankhwala ena okhala ndi mamolekyu ang'onoang'ono (mwachitsanzo, madzi) amatha kudutsa nembanemba mbali zonse ziwiri malinga ndi kuchuluka kwa ndende. Kufalikira kwa ena kumakhala kovuta, ndipo selo lokha limayendetsa mayamwidwe awo. Kuphatikiza apo, makina am'manja amagwiritsidwa ntchito kufalitsa - ma conveyors ndi ma ion.

The conveyor amamanga ion kapena molekyulu ndiyeno amasunthira nayo ku mbali ina ya nembanemba (pamene nembanemba payokha ndi yaying'ono) kapena - ikadutsa mu nembanemba yonse - imasuntha tinthu tosonkhanitsidwa ndikuitulutsa kumapeto kwina. Zoonadi, ma conveyors amagwira ntchito njira zonse ziwiri ndipo ndi "otsika" kwambiri - nthawi zambiri amanyamula mtundu umodzi wokha wa chinthu. Njira za ion zikuwonetsa magwiridwe antchito ofanana, koma njira yosiyana. Akhoza kuyerekezedwa ndi fyuluta. Kuyenda kudzera mu njira za ma ion nthawi zambiri kumatsata kutsika kwa ma ion (kutsika mpaka kutsika kwa ma ion mpaka kutsika). Kumbali inayi, njira za intracellular zimayang'anira kutsegula ndi kutseka kwa ndime. Njira za ion zimawonetsanso kusankha kwakukulu kuti tinthu tidutse.

Ion Channel (kumanzere) ndi mapaipi akugwira ntchito

Bakiteriya flagellum ndi njira yeniyeni yoyendetsera galimoto

Palinso makina ena osangalatsa a ma cell mu nembanemba - flagellum drive, yomwe imatsimikizira kuyenda kwa mabakiteriya. Ichi ndi injini ya puloteni yomwe ili ndi magawo awiri: gawo lokhazikika (stator) ndi gawo lozungulira (rotor). Kuyenda kumachitika chifukwa cha kutuluka kwa ayoni wa haidrojeni kuchokera ku nembanemba kupita ku selo. Amalowa munjira mu stator ndikupitilira gawo lakutali, lomwe lili mu rotor. Kuti alowe mkati mwa selo, ayoni a haidrojeni ayenera kupeza njira yopita ku gawo lotsatira la tchanelo, lomwe lilinso mu stator. Komabe, rotor iyenera kuzunguliridwa kuti mayendedwe agwirizane. Mapeto a rotor, akukwera kupyola khola, amapindika, flagellum yosinthika imamangiriridwa kwa iyo, ikuzungulira ngati propeller ya helikopita.

Ndikukhulupirira kuti mwachidule mwachidule cha makina am'manja kuwonetsetsa kuti mapangidwe omwe adapambana Mphotho ya Nobel, popanda kusokoneza zomwe akwaniritsa, akadali kutali ndi ungwiro wa chilengedwe cha chisinthiko.