Gene Inkulumo - yini lokho? Inchazelo

Yini uwukubonakaliswa izakhi zofuzo? Iyini indima yayo? Kanjani lo mshini isakhi sofuzo inkulumo? Ayini amathemba ivula phambi kwethu? Kushiwo ngamuphi umqondo ukuthi ukulawulwa isakhi sofuzo nkulumo eukaryotes futhi prokaryotes? Nasi uhlu olufushane imibuzo ezophendulwa kulesi sihloko.

ulwazi olujwayelekile

Gene Expression - kuyinto ukudluliswa inqubo igama ukwaziswa kwezakhi zofuzo kusukela DNA nge-RNA ukuba amaprotheni polypeptides. Ake Ukushaya akanhlanhlatsi ukuqonda encane. Yiziphi ezakhini zofuzo? Lokhu komugqa polymers DNA axhunyiwe ngumuntu chain eside. Ukusebenzisa amaprotheni akha chromatin chromosome. Uma sikhuluma umuntu, khona-ke siba amane nesithupha. Basuke eliqhele 50 000-10 000 izakhi zofuzo kanye 3.1 zemakhiwo engamibili. Indlela ziqondiswa lapha? Ubude izigaba lapho umsebenzi wenziwa, kuvezwa izinkulungwane nezigidi nucleotide. Omunye chromosome iqukethe mayelana 2000-5000 zofuzo. Encwadini imigomo kuyiwa - yizigidi ezingu-130 base ngazimbili. Kodwa lena kuphela ukulinganisa imagebhugebhu kakhulu, okuyinto ucishe kweqiniso ngoba ukulandelana ezinkulu. Uma usebenzela phezu amafushane, isilinganiso ziyophulwa. Futhi kule phansi kungawuthinta umzimba, enikezwe umsebenzi wenziwa impahla.

mayelana zezakhi zofuzo

Sinenkosi obuphelele ezihlukahlukene kakhulu. Lapha, ngokwesibonelo, globin - kuyinto 1500 ama-nucleotide. A dystrophin - I-kakhulu ngendlela 2 million! izakhi zabo cis zokulawula ingasuswa kusukela isakhi sofuzo i-ibanga elithileko. Ngakho, ngo-globin zingabantu at ibanga 50 no-30 ama-nucleotide e tysyach 5'- futhi 3'-isiqondiso, ngokulandelana. Ukuba khona inhlangano ezifana kakhulu inkimbinkimbi definition kwethu imingcele phakathi kwawo. Futhi, izakhi zofuzo aqukethe esibalulekile vysokopovtoryayuschihsya Kulandzelanisa yemfanelo obusebenzayo esiye azikaqondakali.

Ukuze uqonde isakhiwo sabo eyodwa Ungacabanga ukuthi Ama-chromosomes e-46 kukhona amavolumu ehlukile, lapho ulwazi olulondolozwe. Basuke zihlelwe zaba 23 ngazimbili. Omunye izakhi ezimbili luthathwe umzali. "Umbhalo," okuyinto e "imiqulu" ngokuphindaphindiwe "kabusha funda" izinkulungwane izizukulwane, okuletha e eziningi amaphutha kanye nezinguquko (ngokuthi ukushintsha izakhi zofuzo okuqondiswa). Futhi zonke esitholakala ngofuzo kubantu inzalo. Manje kukhona ulwazi olwanele theory ukuqala ukubhekana neqiniso lokuthi inkulumo isakhi sofuzo ububonisa. Leli qiniso isihloko eyinhloko kulesi sihloko.

Imfundiso yokuziphendukela operon

Kusekelwe izifundo ezihlukahlukene zofuzo, β-galactosidase lokungeniswa, okuyinto nengxenye cleavage hydrolytic-lactose. Kwakuthinta washayelwa uJacques Monod futhi Fransua Zhakobom. Lo mbono uchaza indlela yokulawula synthesis namaprotheni prokaryotes. Futhi zidlala indima ebalulekile kanye nokubhalwa. Imfundiso ukuthi izakhi zofuzo ngamaphrotheni ukuthi ezisebenza esihlobene izinqubo umzimba, ngokuvamile eqoqelwe ndawonye. Zakha amayunithi kwesakhiwo ngokuthi operons. ukubaluleka wabo uwukuthi zonke izakhi zofuzo ayingxenye ke, wazwakalisa kanyekanye. Ngamanye amazwi, angase udluliswe, noma akekho kubo kungaba "funda". Ezimweni ezinjalo, operon iyasebenza noma kucashile. isakhi sofuzo Inkulumo ezingeni kungashintshwa kuphela uma kukhona iqoqo izakhi ngabanye.

Lokungeniswa wamaprotheni zamagama

Ake sicabange ukuthi sinawo cell okuyinto ekukhuleni yayo njengoba umthombo carbon ukusetshenziswa glucose. Uma ukushintshwa lactose disaccharide, emva kwamaminithi ambalwa ungaba ephephile ukuthi ingashintshwa ukuze izimo ukuthi zishintshile. Ukuthi kukhona incazelo: iseli ongasebenza kokubili imithombo yokukhula, kodwa esinye sazo ngiyo lefanele. Ngakho-ke, kukhona "emehlweni 'kumuntu fabricable chemical kwakwakhe. Kodwa uma kulahleka esikhundleni sayo kwafakwa uHlelo kuvela i-lactose, obhekene RNA polymerase inikwe amandla futhi iqala ukuba nethonya layo phezu ukukhiqizwa amaprotheni oyifunayo. Kuyinto ngaphezulu theory, kodwa manje ake sixoxe indlela langempela isakhi sofuzo nkulumo ivela. Loku kuyajabulisa.

Inhlangano chromatin

Material kwalesi sigaba uyisibonelo lamaseli umahluko we amaningi. Kanti i-nuclei chromatin embondelene ukuze nje umbhalo encane ufuzo iyatholakala (1%). Kodwa naphezu kwalokhu, sibonga cell ukwehluka nokuba yinkimbinkimbi izinqubo ezenzeka kubo singakwazi nomthelela kubo. Okwamanje, i-umuntu itholakala nethonya elingaka inhlangano chromatin:

1. Ukushintsha inombolo zezakhi zofuzo kwesakhiwo.
2. Ngokunenzuzo ukubhala ezingxenyeni ezahlukene ikhodi.
3. Kabusha izakhi zofuzo kuma-chromosome.
4. Yenza ukulungiswa kanye kwemiqondo polypeptide ngamaketanga.

Nokho, inkulumo efanele isakhi sofuzo target kufezwa ngokusebenzisa esiqinile ukunamathela ubuchwepheshe. Kungakhathaliseki ukuthi umsebenzi wenziwa, ngisho noma ukuhlola uyaqhubeka igciwane elincane. Into esemqoka - iwukuba anamathele plan lwentiwe kokungenela.

Ukushintsha inombolo zezakhi zofuzo

Kungenziwa kanjani lokhu lwenteke? Ake sithi sinesithakazelo kwesikwenzayo umphumela isakhi sofuzo inkulumo. Njengoba i-prototype sathatha eukaryote impahla. Uye plasticity okusezingeni eliphezulu, singakwazi ke wenze izinguquko ezilandelayo:

1. Ukuze kwandiswe isibalo zofuzo. Isetshenziselwa ezimweni lapho kubalulekile ukuthi umzimba ikhuphukile synthesis umkhiqizo othize. Ngo isimo enjalo iyakhula izakhi eziningi ewusizo lwezakhi zofuzo zomuntu (isib rRNA, tRNA, histones, nokunye). amasayithi okunjalo kungaba Ngohlelo ngaphakathi kuma-chromosome, ngisho eqele ngalé nabo inani ayizinkulungwane 100 1 million base ngazimbili. Ake sibheke ngokoqobo. Isithakazelo kithi isakhi sofuzo metallothionein. umkhiqizo wayo amaprotheni kungaba uxhumano nomsebenzisi izinsimbi ezisindayo like zinc cadmium, mercury nethusi, ngokulandelana, ukuvikela umzimba kusuka ushevu kubo. ukusebenza kwalo kungaba wusizo kubantu abasebenza ezimweni ezingaphephile. Uma umuntu kukhona i okuhlushwa anda of izinsimbi ezisindayo okukhulunywe ngaye ekuqaleni, ukusebenza isakhi sofuzo kwenzeka kancane ngokuzenzakalelayo.
2. Nciphisa inombolo lokhu ngezakhi ezingamaqoqo. It is kuyaqabukela esetshenziswa indlela yokulawulwa. Kodwa lapha futhi kunezibonelo. Omunye edume kunazo - kuba abomvu egazi. Lapho ikhula, umnyombo ehlala kanye yenethiwekhi ilahlekelwa ufuzo yayo. inqubo okunjalo nokuvuthwa lymphocyte ihlolwe futhi plasma amaseli, ukufaniswa ahlukahlukene ukuthi abangu kuhlelwe umqondo ethakwa izinhlobo immunoglobulin, ayisiza.

isakhi sofuzo rearrangement

Okunye okubalulekile ukuthi kungenzeka ezihambayo ngokuhlanganisa impahla ngawo okwazi umbhalo kanye ukufanisana. Le nqubo ibizwa ngokuthi recombination zofuzo. Ngu yini izindlela kungenzeka? Ake sicabangele izimpendulo zemibuzo impendulo yalo mbuzo ngesibonelo omzimba. Basuke adalwe B-lymphocyte, okungokwendlela uhlobo oluthize Clone ethize. Futhi uma ukuxhumana komzimba antigen lapho omzimba kuba ongumphelelisi nesayithi asebenzayo lokunamathelisa kwenzekani ekwandeni okwalandela amaseli. Kungani-ke ukuthi umzimba womuntu uyakwazi ukudala ezihlukahlukene amaprotheni? Lokhu yenziwe yaba khona recombination futhi ukuguquka kwezakhi zofuzo ukuphathwa kwabathintwayo. Kodwa kungaba umphumela wezinguquko ezenziwe umuntu e isakhiwo DNA.

ushintsho RNA

Gene Expression - kuyinto inqubo lapho kudlala enkulu indima ribonucleic acid. Uma sicabangela mRNA kuyadingeka ukuze wazi ukuthi ngemuva isakhiwo umbhalo oyinhloko zingahluka. Kulandzelana kwalokucuketfwe lokuhleliwe nucleotide ezakhini zofuzo okufanayo. Kodwa ezicutshini ezahlukene mRNA zingavela izisusi, okufakiwe, noma umane ukulahlekelwa kuzokwenzeka imibhangqwana. Njengoba isibonelo kusukela imvelo kungaholela apoprotein B, elakhiwe kumaseli emathunjini amancane futhi isibindi. Yini uhlela umehluko? Le nguqulo ekhishwa amathumbu, has 2152 amino acid. Nakuba okuqukethwe isibindi okufushane inama 4563 esikalini! Futhi naphezu lo mehluko, sinalo ncamashi apoprotein B.

Izinguquko Ezenzeka mRNA ukuzinza

Siye cishe bafinyelela esiphethweni ukuthi kungenzeka ukwenza amaprotheni futhi polypeptides. Kodwa masivume okwamanje sibheke ingalungiswa kanjani mRNA ukuzinza. Ukuze wenze lokhu, ekuqaleni ke kufanele ushiye i-nucleus futhi ukuphuma cytoplasm. Lokhu kufezwa ikhule ezimbotsheni ekhona. Inani elikhulu mRNA is wajinge wanamatsela ngu nucleases. Labo ukuthi ukubaleka kule ukhanda, ahlele izakhiwo kanye amaprotheni. Lifetime of mRNA eukaryotic kuyahlukahluka ezahlukahlukene (izinsuku ezimbalwa). Uma usimamise mRNA ke ngesilinganiso fixed kungenziwa waphawula ukuthi kwenani labafana elalisanda kumiswa amaprotheni umkhiqizo. isakhi sofuzo Inkulumo ezingeni kulokhu asishintshi, kodwa, okubaluleke, umzimba uyobe usebenza nge ngekhono elingcono. Ukusebenzisa amasu ngamangqamuzana ezinto eziphilayo, umphumela wokugcina kungenziwa code, okuzokwenza zibekelwe isikhathi esithile abalulekile. Ngakho, ngokwesibonelo, kungenzeka ukwakha β-globin isebenze amahora angaba yishumi (lokhu kakhulu ke).

inqubo ijubane

Lokho kubhekwa ngokuvamile isakhi sofuzo inkulumo uhlelo. Manje ihlala yodwa ukwelekelela ulwazi olutholakala, ulwazi fast kanjani izinqubo, kanye amaprotheni isikhathi eside. Ake sithi ukulawula isakhi sofuzo Inkulumo izobamba. Kufanele kuqashelwe ukuthi nomthelela izinga akubhekwa indlela eyinhloko esimisweni somthetho ukwehluka kanye nobungako wamaprotheni umkhiqizo. Nakuba ushintsho yayo ukuze sifinyelele lo mgomo isasetshenziswa. Njengoba isibonelo synthesis umkhiqizo iphrotheni reticulocytes. Hematopoietic iseli kwamangqamuzana ezingeni bancishwa nucleus (futhi kungakho DNA). Amazinga isakhi sofuzo Inkulumo imigomo jikelele zakhelwe kuye abanye uhlobo uxhumano amathuba ngenkuthalo ukuthonya izinqubo eziqhubekayo.

Isikhathi

Lapho namaprotheni kwemiqondo, isikhathi lapho yena bayophila incike protease. Kukhona akakwazi ngokuthi ncamashi ngangokunokwenzeka, ngoba kulesi simo zokhahlamba kusuka amahora ambalwa ukuze ngemva kweminyaka embalwa. isivinini proteolysis sehluka kakhulu, kuye ngokuthi yini cell kuba. Enzyme ezingaba catalyze izinqubo bathambekele ngokushesha "esetshenziswa." Ngenxa yalokhu, nazo adalwe umzimba inqwaba. Futhi ku kwempilo amaprotheni kungayithonya isimo bokuphila emzimbeni. Futhi, uma umkhiqizo onesici sidaliwe, kuyothiwa masinyane iqedwe uhlelo zokuzivikela. Ngakho, singasho kugcwale umlomo ukuthi into kuphela kufanele sitshele - lena kwempilo ejwayelekile etholwe endaweni yokucwaninga.

isiphetho

Le ndawo ethembisa kakhulu. Ngokwesibonelo, inkulumo ethi zezakhi zofuzo angaphandle kungasiza ukwelapha izifo ngofuzo, futhi uqede kuguquka ezimbi. Nakuba kunezinkolo onolwazi olunzulu ngale ndaba, singasho kugcwale umlomo ukuthi abantu namanje kuphela ekuqaleni. Ubuchwepheshe bokushintsha izakhi zofuzo usanda kulithola ukwaba izingxenye ledzingekako nucleotide. iminyaka engu-20 adlule kwakungekho omunye izenzakalo ezinkulu kwale sayensi - sidalwe Dolly izimvu. Manje, ucwaningo lwenziwa ku imibungu. Asikwazi ukusho ngokuqiniseka ukuthi singabantwana embundwini esizayo, lapho azikho izifo nokucindezeleka bokuphila. Kodwa singakabi khona, kufanele ube okuhle kakhulu ukusebenza ukuze kuzuze nokuchuma.