Waa maxay chromatin: Qeexidda, qaab-dhismeedka iyo shaqada

waxbarashada lagmamaarmaanna u ah ee genetics - hab muhiim ah inaad wax ka barato oo ay ugu muhiimsan qaybaha - hiddo iyo koromosoomyada. In this article waxaan eegi doonaa waxa chromatin, aad u ogaato in ay qaab-dhismeedka iyo shaqada ee gacanta.

Hiddo - hantida ugu weyn ee arrinta ku nool

Ka mid ah hababka ugu muhiimsan in sifaha noolaha ku nool Dhulka, waxaa neefsashada, nafaqada, koritaanka, xulashada iyo taranka. function ugu danbeysay ee waa kuwa ugu muhiimsan ilaalinta nolosha on dhulkeenna. Sidee in aan xusuustaa in Qaynuunkii kowaad la siiyo by Ilaah in Aadan iyo Xaawo waxay ahayd soo socda: ". Wax badan dhala, oo tarma" At heerka unugyada function generative waxaa la sameeyaa iyadoo acids nucleic (walax dastuurka ee koromosoom). qaababka waxaa la hadli doonaa waxa soo socota.

Waxaan sidoo kale ku dar in ilaalinta iyo gudbinta macluumaad hidde u qaadeen oo durriyadii hab la mid ah in aanu ku xiran tahay heerka urur ah oo ay shakhsiyaad, in uu yahay, waayo fayraska iyo bakteeriyada, oo waa universal si aadanuhu.

Waa maxay maalkiisu hiddo

In warqad this waxaan ku baran dhismeedka chromatin iyo hawlaha kuwaas oo si toos ah ay ku xidhan tahay ururka ee u taagoo acid nucleic. Miescher saynisyahan Swiss ee 1869 xeryahooda ayaa la ogaado in ay nuclei unugyada ee habka difaaca jirka, soo bandhigista sifooyinka acids u yeedhay nukleina hore iyo acids markaas nucleic. Eegaysana ee kimistari, waxaa macromolecular xarunta - polymers. monomers Kuwanu waa nucleotides isagoo qaab dhismeedka socda: purine ama saldhig pyrimidine, oo ka hadhay pentose of orthophosphoric acid. Seynisyahanno ku ogaaday in laba nooc oo acids nucleic joogo in unugyada waxaa laga yaabaa: DNA iyo RNA. Waxay yihiin complexed la borotiinada si ay u sameeyaan xarunta ah koromosoomyada. Iyo sidoo kale borotiinada, acids nucleic leeyihiin heerar kala duwan ee ururka da'ayeen.

In 1953 abaalmarinta Nobel Prize ahaa Watson oo Crick tarjunto qaabka DNA. Waxaa Britain ka kooban labada silsiladood oo isku xidhan by bonds hydrogen timi dhexeeya saldhig nitrogenous on mabda'a complementarity (saldhig thaymiin adenayn soo horjeeda ku yaal saytosayn soo horjeeda - gu'anayn). Qaab dhismeedka Chromatin iyo shaqada oo aan la waxbarasho, Britain ayaa wuxuu ka kooban yahay acid ah deoxyribonucleic iyo gaadmada ah ee kala duwan ribonucleic. On arrintan, waxaan hadal si tifatiran qaybta "Heerarka urur chromatin."

Deegaamaynta ah maalkiisu hiddo in gacanta

DNA ku sugan, kuwaas oo cytostructure sida asaasiga ah, iyo sidoo kale in organelles, oo awood u qaybinta - mitochondria iyo chloroplasts. Tan waxa u sabab xaqiiqada ah in organelles kuwaas qabtaan hawlo muhiim ah in unugyada: Avv ATP, iyo ereygu wuxuu ahaa ee glucose iyo formation oxygen ee unugyada dhirta. organelles dardaro talaabo waalidka Laab meertada nolosha. Sidaas darteed, unugyada gabadhii ugu maytosis ah (qaybinaya unugyada degaaankaaga) ama meiosis (formation of shahwad iyo ridani) ay awoodi karaan dhismeedka gacanta Arsenal la doonayo siiyaan unugyada la nafaqada iyo tamarta.

Ribonucleic acid waxay ka kooban tahay mid ka mid silsilad ah oo uu leeyahay miisaan hoose kelli badan DNA. Waxay heleen in xuduntii iyo hyaloplasm, iyo waa qayb ka mid ah organelles badan cell: ribosomes, mitochondria, reticulum endoplasmic, plastids. Chromatin in organelles, kuwaas oo la xidhiidha protein histone iyo qayb ka mid ah plasmids ah - xiran wareeg ah u taagoo DNA.

Qaab dhismeedka Chromatin iyo

Sidaas awgeed, waxaan ku adkeeyey in acid ee nucleic ku jira walax ee koromosoom - unugyada dhismaha ee hiddo. Ay chromatin microscope electron hoostiisa ayaa qaab granular ama dhismayaasha filamentous. Waxaa ku jira, ka sokow DNA ah, iyo xataa taagoo RNA, iyo brotiin soo bandhigista guryaha aasaasiga ah iyo histones magacaabay. All of kor ku xusan dhismayaasha waa qayb ka mid ah nucleosome. Waxay waxaa laga helaa xuduntii koromosoomyada ah waxaa loo yaqaan fibrils (thread-solenoids). Koobaya kor ku xusan oo dhan, waxaan go'aan ka in chromatin this. Xarunta Tani adag ee acids deoxyribonucleic iyo borotiinada gaar ah - histones. Waxay, sida gariiradda ah, waxaa lagu dhaawacaa taagoo double-ku xayiran DNA si ay u sameeyaan nucleosome ah.

Heerarka Ururka chromatin

walax hiddo leedahay qaab kala duwan, taas oo ku xidhan tahay qodobo badan. Tusaale ahaan, waxa stage of unugyada nolosha wareegga marista ah: qaybinaya muddada (metoz ama meiosis), ama presynthetic dardaro inta lagu guda jiro interphase. Laga soo bilaabo qaab solenoid ah, ama fibrils, sida ugu fudud, waxaa jira compaction dheeraad ah chromatin. Heterochromatin - state a more cufan, waxaa la aasaasay in qaybo intron ee koromosoom ah, taas oo aan qoraal suurto gal ah. Inta lagu guda jiro unugyada inta kale - interphase, marka uu jiro nidaamka qaybinta lahayn - karyoplasm heterochromatin ku yaalla xuduntii peripherally, dhow xuub. Dhagixiina way ku jira nuclear-yada postsynthetic dhacdaa wareegga nolosha unugyada, i.e. isla markiiba ka hor inta qeybinta.

Maxaa go'aamiso uumiga ee arrinta of hiddo

Sii si ay u sahamiyaan su'aasha "waxa chromatin," cilmi lagu ogaaday in ay ku xiran tahay borotiinada seal-histone in, oo ay weheliyaan ee u taagoo ee DNA iyo RNA ee nucleosome ah. Waxay ka kooban yihiin afar nooc oo borotiin, loo yaqaan sac iyo linker. Waqtigan xaadirka ah ee qoraal (reading macluumaadka ka hiddo-via RNA) wax hiddo liidata dhisnayd, oo waxaa lagu magacaabaa euchromatin.

Currently qaybinta gaar ah u taagoo DNA ee la xidhiidha borotiinada histone lagu bartay. Tusaale ahaan, cilmi ogaaday in chromatin loci kala duwan ee koromosoom isla heerarka kala duwan ee uumiga. Tusaale ahaan, meelaha of lifaaqa u filaments koromosoom dunmiiqa mitotic yeedhay centromeres, waxay u badan tahay daar qaybaha telomeric - dhamaadka loci.

Hiddo-nidaamiyo oo chromatin

Fikradda ah sharciyeynta dhaqdhaqaaqa hiddo, abuuray by geneticists Faransiis Yacquub iyo Monod, ku siinayaa fikrad ah jiritaanka goobaha deoxyribonucleic acid, taas oo ay jirto wax macluumaad ah oo ku saabsan qaab dhismeedka of protein ah. Wayna oofiyaan a Gaarna maamul - hawlaha maamulka. Magacaabayo nidaamiyo hiddo, kuwaas oo qaybo ka mid ah koromosoomyada sida caadiga ah ee qaab-dhismeedka borotiinada ay maran-histone. Chromatin, qeexidda kaas oo lagu fuliyay by horumarintooda, ayaa loo magacaabay furan.

Baaritaano dheeraad ah waxaa laga dhex helay in loci waxay joogaan xigxiga nucleotide in laga hortago u hogaansanaanta u taagoo DNA qayb protein ah. qaybood oo noocan oo kale ah ka kooban ee hiddo-sharciyeed waa: dhiirrigeliyeyaasha ehansery activators. compaction ee chromatin iyaga la soo galo waa heer sare ah, oo dhererkeeduna wuxuu ka mid ah celceliska qaybaha 300 nm. Waxaa jira hab lagu ogaanayo chromatin ku lagmamaarmaanna u furan in nuclei go'doon, taas oo isticmaalka enzyme DNA-Åse. si dhakhso ah wuxuu jabo loci ee koromosoom, borotiinada maqnaato-histone. Chromatin ee goobahaasi ayaa u yeedhay xasaasiyad.

Doorka walax hiddo

Kaxeynayo oo ay ku jirto DNA, RNA iyo protein yeedhay chromatin, ku lug ontogeny cell iyo bedeli ay ka kooban ku xidhan nooca nudaha iyo marxaladda horumarinta ee u shaqeeyo ah oo dhan. Tus, ee unugyada maqaarka hiddo sida ehanser iyo horumariyaha hor istaagay repressors borotiinada, oo kuwanuna waxay hiddo-nidaamin ee unugyada secretory of epithelium xiidmaha iyo firfircoon ee degaanka of chromatin furan. Qubarada, geneticists ogaaday in at jajab ah DNA aan encode borotiinada, xisaabiyenimo ka badan 95% ee hiddawadayaasha aadanaha. Taas macnaheedu waxa weeye in ay gacanta ku hiddo taasaa ka sii wanaagsan kuwa mas'uulka ka ah ereygu wuxuu ahaa ee peptides. hordhaca ah ee farsamooyinka sida chips DNA iyo horumarintooda ogol yahay in la ogaado waxa chromatin ah, oo ay sabab u tahay, in khariidada hiddawadayaasha aadanaha.

Studies of chromatin waxaa muhiim ah in meelaha sida sayniska sida genetics aadanaha iyo genetics caafimaad. Tani waxay la xidhiidhaa heer xadaa of dhacdo cudurada la iska dhaxlo - hiddo sida iyo koromosoomyada. goor hore la ogaado syndromes kuwaas kordhiyaa boqolleyda saadaasha wanaagsan ee ay daaweynta.