Tanthauzo, kapangidwe ndi ntchito: chromatin Kodi

maphunziro amuzolengedwa chibadwa - njira yofunika kwambiri kuphunzira zigawo zikuluzikulu - majini ndi DNA. M'nkhaniyi tiona zimene chromatin, tikupeza akuphatikizapo ntchito mu selo.

Chibadwa - chuma chachikulu cha nkhani moyo

Mwa njira zazikulu zomwe majeremusi amene akukhala pa dziko, ndi kupuma, zakudya, kukula, kusankha ndi kubalana. Ntchito otsiriza ndi zofunika kwambiri kuteteza moyo padziko lathuli. Kodi si kukumbukira kuti lamulo loyamba Mulungu anapatsa Adamu ndi Hava anali kutsatira: ". Mubalane muchuluke" Pa mlingo wa maselo ntchito zobereka imagwiridwa ndi zidulo mkati (constituent mankhwala DNA). nyumba Tikambirana zomwe motere.

Ifenso kuwonjezera kuti kuteteza ndi kufala kwa uthengawu ku maselo adatengedwa ndi ana a limagwirira yemweyo amene sadalira pa mlingo wa gulu la anthu, kuti ndi HIV ndi mabakiteriya, ndipo konsekonse anthu.

Kodi chinthu cha chibadwa

Mu pepala ili timaphunzira chromatin kapangidwe ndi ntchito za amene ali mwachindunji amadalira gulu la tinthu mkati acid. Swiss wasayansi Miescher mu mankhwala 1869 anali wapezeka mu mtima wa maselo a chitetezo cha m'thupi, naonetsere katundu zidulo anawaitana woyamba nukleina ndi zidulo ndiye mkati. Kwa zasayansi, izo macromolecular pawiri - ma polima. monomers Awa nucleotides ndi kapangidwe otsatirawa: a purine kapena pyrimidine m'munsi, ndi pentose zotsalira asidi orthophosphoric. Asayansi apeza kuti mitundu iwiri ya zidulo mkati akhoza kupezeka mu maselo: DNA ndi RNA. Iwo complexed ndi mapuloteni kupanga pawiri DNA. Komanso mapulotini, zidulo mkati ndi milingo angapo a bungwe okhudza malo.

Mu 1953 ndi Nobel Prize anali Watson ndipo Crick kuwerenga kapangidwe ka DNA. Ndi molekyulu wapangidwa ndi maunyolo awiri cholukanalukana mwa maunyolo a hydrogen akuwuka pakati zapansi nitrogenous pa mfundo za mapolojekiti (zosiyana adenine thymine m'munsi ili zosiyana cytosine - guanine). Chromatin kapangidwe ndi ntchito zimene tikuphunzira, molekyulu zizindikiro deoxyribonucleic acid ndi ribonucleic masanjidwe zosiyanasiyana. Pa nkhani imeneyi, tikambirana mwatsatanetsatane mu chigawo "Akukwera wa chromatin bungwe."

Kutanthauzira wa chinthu cha chibadwa mu chipinda

DNA alipo mu cytostructure izi monga pakati, komanso organelles, angathe magawano - mitochondria ndi chloroplasts. Ichi ndi chifukwa chakuti organelles awa ntchito zofunikira mu selo: kaphatikizidwe ATP, ndi kaphatikizidwe wa shuga ndi mapangidwe mpweya chomera maselo. Kupanga organelles mwatsatane kholo kawiri lifecycle. Choncho, maselo mwana pa mitosis (kugawa somatic maselo) kapena meiosis (mapangidwe umuna ndi umakakumana) linapatsa anakhumba nyumba nkhokwe selo zimene maselo ndi zakudya ndi mphamvu.

asidi Ribonucleic tichipeza unyolo chimodzi ndipo ali m'munsi maselo kulemera kuposa DNA. Iye m'zinthu phata ndi hyaloplasm, ndipo ndi mbali ya organelles ambiri selo: ribosomes, mitochondria, endoplasmic reticulum, plastids. Chromatin mu organelles izi kugwirizana ndi histone mapuloteni ndi gawo la plasmids wa - zozungulira chatsekedwa DNA mamolekyulu.

Chromatin kapangidwe ndi

Kotero ife anakhazikitsa kuti asidi mkati ali ndi thunthu DNA - ndi mayunitsi structural cha chibadwa. chromatin awo pansi pa elekitironi maso ali mawonekedwe a granular kapena nyumba filamentous. Lili kusiya DNA, ndipo ngakhale mamolekyulu RNA, komanso mapulotini naonetsere katundu zikuluzikulu ndi dzina histones. Zonsezi pamwambapa nyumba ndi mbali ya nucleosome. Zikupezeka phata ndi DNA amatchedwa fibrils (ulusi-solenoids). Mwachidule pamwamba pa zonse, tingadziwe kuti chromatin izi. Izi pawiri zovuta zidulo deoxyribonucleic ndi mapuloteni yeniyeni - histones. Iwo, monga coils, kodi chilonda awiri Shackleton DNA mamolekyulu kupanga nucleosome.

Kuchuluka kwa chromatin gulu

chibadwa mankhwala ali ndi dongosolo zosiyanasiyana kumatengera zifukwa zambiri. Mwachitsanzo, kodi siteji ya moyo mkombero likufa selo: kugawa nthawi (metoz kapena meiosis), kapena presynthetic kupanga pa interphase. Mawonekedwe a solenoid, kapena fibrils, ngati zophweka kwambiri, pali compaction winanso wa chromatin. Heterochromatin - boma kwambiri wandiweyani, aumbike mwa intron mbali ya khromozomu, amene si zotheka galamafoniyo. Pa maselo ena - interphase, pamene palibe ndondomeko magawano - heterochromatin karyoplasm ili mu phata la peripherally, pafupi Kakhungu ake. Kusindikiza nkhani nyukiliya siteji postsynthetic akupezeka mkombero moyo maselo, i.e. asanalankhule magawano.

Kodi Mzimuyo ndi condensation a nkhani cha chibadwa

Kupitiriza kufufuza funso "kodi chromatin," ofufuza anapeza kuti izo zimatengera mapuloteni chisindikizo-histone, limodzi ndi mamolekyulu ya DNA ndi RNA mu nucleosome lapansi. Iwo zigwirizana amitundu inayi mapuloteni, wotchedwa ng'ombe ndi linker. Pa nthawi galamafoniyo (powerenga za mfundo jini kudzera RNA) chibadwa zinthu bwino zinaphatikizidwa, ndipo amatchedwa euchromatin.

Panopa yogawa makamaka a mamolekyulu DNA kugwirizana ndi mapuloteni histone ali akuphunziridwa. Mwachitsanzo, ofufuza anapeza kuti chromatin osiyana loci wa chomwecho khromozomu magulu a condensation. Mwachitsanzo, mu malo a ubwenzi ndi mitotic spindle filaments khromozomu otchedwa centromeres, ndi wandiweyani kuposa zigawo telomeric - kumapeto loci.

Chibadwa-owongolera ndi chromatin

Lingaliro la lamulo la zochitika jini, analengedwa ndi French geneticists Yakobo ndi Monod, apereka aliko m'madera a deoxyribonucleic acid, imene palibe zokhudza kapangidwe ka mapuloteni ndi. Iwo amachita chinthu malamulo - kagwiridwe ka ntchito. Anangotchula majini owongolera, mbali izi DNA kawirikawiri mu dongosolo lake lopanda-histone mapuloteni. Chromatin, tanthauzo imene ikuchitika ndi molumikiza, dzina lake lotseguka.

Mu kuwonjezera maphunziro chinapezeka kuti pa loci izi zili ndi nyukiliotayidi zinayendera kuti kuteteza kutsatira mamolekyulu DNA ndi tinthu mapuloteni. malemba akupanga majini zolimbana ndi: ochirikiza ehansery activators. The compaction wa chromatin mwa iwo ndi mkulu, ndi kutalika kwa zigawo ndi zaka pafupifupi 300 nm. Pali njira kwa kudziŵa amuzolengedwa lotseguka chromatin mu mtima lakutali amene ntchito ya DNA-ase enzyme. Mwamsanga imaphwanya loci DNA, akusowa-histone mapuloteni. Chromatin m'madera amenewa umatchedwa hypersensitive.

Udindo wa chibadwa mankhwala

Maofesi kuphatikizapo DNA, RNA ndi mapuloteni otchedwa chromatin, nawo ontogeny selo ndi kusintha kapangidwe kake malingana mtundu minofu ndi pa siteji ya chitukuko cha chamoyo wonse. Mwachitsanzo, mu maselo zaminyewa wa khungu majini monga ehanser ndi kulimbikitsa oletsedwa mapuloteni repressors, ndi majini izi zolimbana mwa maselo secretory wa epithelium matumbo ndipo ndife achangu m'dera la chromatin lotseguka. Asayansi, geneticists anapeza kuti pa nusu ya DNA kuti musakhale encode mapuloteni, mlandu pa 95% ya matupi a anthu. Izi zikutanthauza kuti ulamuliro jini kwambiri kuposa amene ali ndi udindo kaphatikizidwe wa mapeputisayidi. Mawu oyamba a maluso monga tchipisi DNA ndi molumikiza wandilora kupeza zimene chromatin, ndi chifukwa, ku mapu matupi a anthu.

Studies ya chromatin n'kofunika m'madera omwe ya sayansi monga chibadwa anthu ndi chibadwa zachipatala. Izi kugwirizana ndi mlingo zikuchepa kuchuluka kwa yatsoka matenda otengera - monga jini ndi khromozomu. kuzindikira mwamsanga syndromes izi kumaonjezera kuchuluka Zoneneratu abwino mankhwala.