Kuyini chromatin: definition, lokuphatselene nesakhiwo nemsebenti

izifundo kwamakhemikhali zofuzo - kuyindlela ebalulekile ukufunda izingxenye zalo eziyinhloko - izakhi zofuzo kanye zofuzo. Kulesi sihloko sizohlola yini chromatin, thola isimo sawo futhi umsebenzi kuseli.

Ufuzo - impahla eyinhloko eziphilayo ndaba

Phakathi izinqubo main agcwele izinto eziphilayo ezihlala emhlabeni, kuthiwa ukuphefumula, umsoco, ukukhula, ukukhethwa nasekuvezeni izithombo zaso ezintsha. Umsebenzi wokugcina iyona ebaluleke kakhulu ukuze kulondolozwe ukuphila kule planethi yethu. Kanjani ukuba sikhumbule ukuthi ungowokuqala enikezwa nguNkulunkulu Adamu no-Eva kwaba okulandelayo: ". Zalani nande" Ezingeni amaseli umsebenzi okuzala wenziwa nge acid nucleic (imfuyo ephambili wama-chromosomes). Lezi zakhiwo, kuzoxoxwa ngakho lokho okuyolandela.

Siphinde engeza ukuthi ukugcinwa yokudlulisa ulwazi zofuzo eyalo inzalo indlela efanayo akuxhomekile ezingeni yenhlangano abantu, okungukuthi i-virus namagciwane, futhi kuba jikelele abantu.

Uyini umnyombo ufuzo

Kuleli phephandaba sitadisha isakhiwo chromatin nemisebenzi okuyizinto encike ngqo kwi inhlangano nucleic acid molecule. Swiss usosayensi Miescher ngo-1869 compounds zitholiwe nuclei lamaseli kwesimiso somzimba sokuzivikela ezifweni, bembonisa izakhiwo acid wababiza nukleina kuqala futhi acid ke nucleic. Ngokombono i-chemistry, ke macromolecular kwakwakhe - polymers. Lezi monomers kukhona ama-nucleotide kokuba isakhiwo ezilandelayo: a purine noma isizinda pyrimidine, futhi ezisalayo pentose ka orthophosphoric acid. Ososayensi bathole ukuthi izinhlobo ezimbili acid nucleic zingase amaseli: i-DNA ne-RNA. Basuke complexed ne amaprotheni ukwakha kwakwakhe lezakhi zofuzo. Kanye amaprotheni, amino nucleic amazinga amaningi yenhlangano ngekwendzawo.

Ngo-1953 Umklomelo kaNobel kwaba Watson Crick ziqala ukwakheka DNA. Kuyinto molecule sakhiwa ngamaketanga amabili oxhumene by hydrogen izibopho ezivukayo phakathi izisekelo nitrogen ku isimiso complementarity (okuphambene ne-thymine adenine ihambisane base elise-cytosine okuphambene - guanine). lokuphatselene nesakhiwo nemsebenti zazo sifundela Chromatin, i-molecule ye yakhiwa deoxyribonucleic acid kanye ribonucleic ukucupha ehlukahlukene. Kule ndaba, sixoxa kabanzi esigabeni "Amazinga chromatin inhlangano."

Kwasendaweni we ketshezi ufuzo kuseli

DNA samanje kulezi cytostructure njengoba nje nengaphakathi futhi e organelles, uyakwazi division - mitochondria futhi chloroplast. Lokhu kungenxa yokuthi la organelles enza imisebenzi ebalulekile kuseli: zamagama ATP, kanye zamagama glucose ne-oksijini kwetinhlavu plant cells. organelles Zokwenziwa ushiya sokuphila umzali kabili. Ngakho, amaseli indodakazi at mitosis (sokuhlukanisa amaseli ukuphathwa kwabathintwayo) noma meiosis (kumiswa isidoda kanye ova) lithole oyifunayo arsenal iseli izakhiwo ahlinzeke amaseli izakhi namandla.

Ribonucleic acid siqukethe eyodwa uchungechunge futhi isisindo ephansi yamangqamuzana kuka-DNA. Wathola kokubili nucleus futhi hyaloplasm, futhi kuyingxenye eziningi cell organelles: ribosomes, mitochondria, reticulum endoplasmic, plastids. Chromatin kulezi organelles elihlobene ne histone protein ne ingxenye plasmids - isiyingi avaliwe molecule e-DNA.

isakhiwo Chromatin futhi

Ngakho sesisungule ukuthi nucleic acid eziqukethwe izidakamizwa wama-chromosomes - amayunithi isakhi sofuzo. chromatin zabo ngaphansi ngesibonakhulu electron ine uhlobo luyimbudumbudu noma izakhiwo filamentous. Iqukethe, ngaphandle-DNA, ngisho ama-molecule RNA, namaprotheni bembonisa izakhiwo eziyisisekelo futhi histones okuthiwa. Konke okungenhla izakhiwo ayingxenye nucleosome. Batholakala ku-nucleus futhi chromosome abizwa ngokuthi fibrils (ngentambo-solenoids). Kufinyeta bonke ngenhla, sithola ukuthi lokhu chromatin. Le ngxube eziyinkimbinkimbi of acid deoxyribonucleic namaprotheni ethize - histones. Njengalezi ohlobo, kuthiwa nilimaza kabili balahleke molecule e-DNA ukwakha nucleosome.

Amazinga chromatin inhlangano

ufuzo izidakamizwa has a isakhiwo ehlukene, okuyinto kuxhomeke ezicini eziningi. Ngokwesibonelo, yini esiteji wempilo ubhekene cell: sokuhlukanisa inkathi (metoz noma meiosis), noma zokwenziwa presynthetic isikhathi interphase. Kusukela ngesimo Solenoid, noma fibrils, njengoba iningi elula, kukhona compaction obengeziwe chromatin. Heterochromatin - isimo ayazika, yakheke ku izingxenye intron we-chromosome, okuyinto akunakwenzeka umbhalo. Phakathi nalo lonke amaseli - interphase, uma kungekho inqubo division - karyoplasm heterochromatin elise-nucleus peripherally, eduze ulwelwesi yayo. Uphawu okuqukethwe zenuzi esiteji postsynthetic kwenzeka emjikelezweni wokuphila amaseli, isb ngokushesha ngaphambi division.

Yini enquma ukufingqa ndaba ufuzo

Ukuqhubeka ukuhlola umbuzo "kuyini chromatin," Abacwaningi bathola ukuthi kuncike amaprotheni uphawu-histone ukuthi, kanye molecule DNA ne-RNA ku nucleosome. Zakhiwa izinhlobo ezine amaprotheni, ngokuthi izinkomo futhi linker. Okwamanje of umbhalo (ukufunda ulwazi isakhi sofuzo nge RNA) ufuzo impahla kahle tho, futhi ubizwa ngokuthi euchromatin.

Okwamanje ukusatshalaliswa oluthile molecule e-DNA elihlobene ne histone kwamaprotheni lafundvwako. Ngokwesibonelo, abacwaningi bathola ukuthi chromatin loci ezahlukene chromosome amazinga afanayo ezahlukene ukufingqa. Ngokwesibonelo, ezindaweni ukunamathela mitotic lokuphotha chromosome sesigcilikisha ngokuthi centromeres, kuba obukhulu ezingaphezu kuka izigaba telomeric - ekupheleni loci.

Zofuzo-nabalawuli kanye chromatin

Umqondo ukulawulwa umsebenzi isakhi sofuzo, adalwe zofuzo French uJakobe futhi Monod, kunikeza umbono wokuba khona izindawo-deoxyribonucleic acid, lapho kungekho ulwazi mayelana nesakhiwo amaprotheni. Enza luyingxenye bureaucratic - imisebenzi zokuphatha. Ukwetha izakhi zofuzo nabalawuli, lezi zitho chromosome ngokuvamile oyiyo elingenalo-histone amaprotheni. Chromatin, kwencazelo okwenziwa ngu ngekulandzelanisa, yaqanjwa ngokuthi evulekile.

Ngo nezifundo kwatholakala ukuthi lezi loci elise nucleotide ukulandelanisa, ekuvimbeleni ukunamathela molecule e-DNA ye-kuyizinhlayiyana amaprotheni. izingxenye ezinjalo zimumethe zofuzo yilezi: abagqugquzeli ehansery activators. I compaction we chromatin kuwo uphakeme, ubude zalezi zingxenye ezomhlaba mayelana 300 nm. Kukhona indlela yokunquma chromatin evulekile kwamakhemikhali nuclei uwedwa ukusetshenziswa enzyme-DNA-ASE. Ngokushesha ahlahlele loci wama-chromosomes, iyantuleka histone amaprotheni. Chromatin kulezi zindawo futhi iye yachazwa ngokuthi hypersensitive.

Indima ufuzo izidakamizwa

Izakhiwo ne-DNA, i-RNA futhi iprotheni ebizwa ngokuthi i chromatin, abathintekayo kuseli ontogeny futhi siguqula ngezithako zawo kuye ngohlobo kwezicubu esiteji ukuthuthukiswa i umzimba iyonke. Isb, kumaseli EPITHELIAL kwesikhumba izakhi zofuzo ezifana ehanser futhi umgqugquzeli ivinjiwe amaprotheni repressors, futhi lezi zofuzo kumaseli secretory we epithelium emathunjini futhi bamatasa endaweni chromatin evulekile. Ososayensi, izazi zezakhi zofuzo zathola ukuthi emaphethelweni e ingxenyenamba DNA musa encode amaprotheni, ama-95% zofuzo lomuntu. Lokhu kusho ukuthi control isakhi sofuzo kungaphezu labo banesibopho synthesis peptides. Ukwethulwa emasu lafana chips ne-DNA nezinto • Ukutshengisa ukulangazelela nokuthatheka bavunyelwe ukuthola ukuthi yini ezokwenzeka chromatin, futhi ngenxa yalokho, ukuze Imebhe amangqamuzana ezakhi zofuzo zomuntu.

Ucwaningo chromatin kubalulekile ezindaweni ezifana nesayensi ezifana zofuzo lomuntu futhi zofuzo wezokwelapha. Lokhu lihlotshaniswa ezingeni okwanda nesenzakalo izifo lezinceku - isakhi sofuzo efana futhi chromosome. Ukusheshe lezi syndromes kwandisa iphesenti izibikezelo omuhle ekwelashweni kwabo.