Tlhaloso, sebopeho le mosebetsi: chromatin ke eng

lithuto tsa skeletal ka liphatsa tsa lefutso - tsela ea bohlokoa ea ho ithuta metsoako e ka sehloohong - liphatsa tsa lefutso le ho chromosomes. A sehloohong sena a re tla sheba hore na ke chromatin, fumana ho sebopeho sa eona 'me mosebetsi ka seleng.

Lefutso - thepa ka sehloohong sa taba e phelang

Har'a dithulaganyo tsa sehlooho tseo khethollang phelang eo phela ka Earth, ba hema, phepo e nepahetseng, khōlo, khetha le ho ikatisa. Mosebetsi ho qetela ke ea bohlokoa ka ho fetisisa bakeng sa ho pholosa bophelo ba ka lefatšeng. Kamoo a se ke a hopola hore molao oa pele e fanoeng ke Molimo ho Adama le Eva e ne e le tse latelang: ". Atang le atisa" Ha boemo ba lisele tsa mosebetsi ho ikatisa o etsoa ka acid nucleic (constituent boleng ba sebele ba chromosomes). dibopeho tsena li tla tšohloa eng latelang.

Re boetse re eketsa hore ho pholosa le phetiso ea boitsebiso bo liphatseng tsa lefutso bo jaloang ke litloholo tsa mochine o tšoanang le oo ha ea itšetleha ka boemo ba mokhatlo oa batho ka bomong, e le hore ke bakeng sa kokoana-hloko 'me libaktheria li,' me ho ke ke bokahohleng ho batho.

ke eng boleng ba sebele ba lefutso

Ka pampiri ena re ithuta chromatin sebopeho le mesebetsi ya tse ka kotloloho itšetleha ka mokhatlo o hlophisitsoeng oa limolek'hule nucleic acid e. Switzerland rasaense Miescher ka metsoako 1869 li ne li lemoha ka nuclei ea lisele tsa boitshireletso ba mmele, ba bontša thepa ea acid ba bitsa pele nukleina le acid ebe nucleic. Ponong ea k'hemistri, ho macromolecular komponeng - polymers. monomers tsena ke nucleotides ho ba le sebopeho sa tse latelang: a purine kapa pyrimidine botlaaseng, 'me pentose masalla ea acid e orthophosphoric. Bo-rasaense ba fumane hore mefuta e 'meli ea acid nucleic le ka ho ba teng ka lisele tsa tsona li: DNA le RNA. Di complexed le liprotheine ho theha e motsoako oa chromosomes. Hammoho le lihaha-'mele, acid nucleic na maemo a mangata ea mokhatlo oa tlhaloganya sebaka.

Ka 1953 Khau ea Nobel e ne Watson le Crick deciphered sebōpeho sa DNA. Ke molek'hule entsoe ka liketane tse peli ya kokangana ka litlamo hydrogen hlahang pakeng tsa makalana nitrogenous ka molao-motheo oa complementarity (bo fapaneng adenine thymine botlaaseng teng bo fapaneng cytosine - guanine). Chromatin sebopeho le mosebetsi oa oona e re ho ithuta, ka molek'hule kenyelletsa ditokiseletso e acid e deoxyribonucleic le ribonucleic diphetolo tse sa tšoaneng. Ka taba ena, re buisana ka ho qaqileng ho feta karolong e "maemo a chromatin mokhatlo o hlophisitsoeng."

Diriswa ya boleng ba sebele ba lefutso ka seleng

DNA teng cytostructure tsena e le ea mantlha ea, 'me hape le ka organelles, ea nang le bokhoni ea karohano - mitochondria le chloroplasts. Sena ke ka ntlha ya go ha e le hantle hore organelles tsena phetha mesebetsi bohlokwa ka seleng: tswakana ATP, le tswakana ya tsoekere le sebopeho oksijene liseleng semela. Maiketsetso organelles hata motsoali oa habeli lifecycle. Kahoo, lisele tsa morali oa ka mitosis (arola somatic lisele tse) kapa meiosis (sebopeho sa peō ea botona le ova) fana ka a lakatsa dibopeho pokellong seleng e fana ka lisele le limatlafatsi tse ngata le matla.

asiti Ribonucleic na le ketane e mong le o na le e ka tlaase ea limolek'hule boima ho feta DNA. O ile a fumana bobedi ka khubung le ka hyaloplasm, 'me ke karolo ea organelles tse ngata ke le seleng: ribosomes, mitochondria, endoplasmic reticulum, plastids. Chromatin ka organelles tsena tse amanang le histone protheine le karolo ea plasmids e - chitja koetsoeng DNA limolek'hule.

Chromatin sebopeho le

Kahoo re ile ra theha hore acid e nucleic leng ka boleng ba sebele ba chromosomes - the diyuniti mehaho ea lefutso. chromatin bona tlasa elektrone ya microscope o na le mofuta o mong oa granular kapa mehaho e filamentous. E na le, ntle ho DNA, 'me esita le limolek'hule tsa RNA, le liprotheine bontša thepa ea motheo le e mong ea bitsoang histones. All ho tse ka holimo dibopeho tse karolo ea nucleosome. Li fumanoa ka khubung ea le chromosomes ba bitsoa fibrils (thread-solenoids). Akaretsa ka holimo ho tsohle, re etsa qeto ea hore chromatin ena. Sena lobed rarahaneng ea acid deoxyribonucleic le liprotheine itseng - histones. Ba, joaloka makhetlo, na qetellong habeli-tsielehile DNA limolek'hule ho theha e nucleosome.

Maemo a chromatin mokgatlo

lefutso ntho e na le sebopeho fapaneng, e leng se itšetlehile ka lintho tse ngata. Ka mohlala, ka seo sethaleng ea bophelo ka potoloho alashwa seleng ea: ho arola nako ea (metoz kapa meiosis), kapa presynthetic maiketsetso nakong interphase. From mokgwa wa solenoid, kapa fibrils, e le tse sa rarahanang ka ho fetisisa, ho na le ke compaction eketsehileng chromatin. Heterochromatin - boemong ho feta le letso-letso, e thehoa ka intron likarolo tse ling tsa chromosome, e leng ke ke ha khoneha mongwalollo. Nakong ea lisele tse ling kaofela - interphase, ha ho sa ho na thulaganyou e karohano - heterochromatin karyoplasm teng khubung ea peripherally, haufi le lera lona. Tiisoa ha dikahare tsa nyutlelie sethaleng postsynthetic le hlaha ka potoloho ea bophelo ea lisele, i.e. hang-hang pele ho karohano.

Seo etsang qeto le condensation ea taba tsa lefutso

Ho tsoela pele ho hlahloba potso e reng "se chromatin," bafuputsi ba fumane hore ho itšetlehile ka liprotheine tiiso-histone eo, hammoho le limolek'hule tsa DNA le RNA ka nucleosome ena. Ba akarelletsa ho mefuta e mene ea lihaha-'mele, bitsoa likhomo le linker. Ka motsotso oa mongwalollo (ho bala ya tlhahisoleseding ho tswa phatsa ea lefutso ka tsela RNA) lefutso tse bonahalang hampe fused, 'me o bitsoa euchromatin.

Jwale kabo ho khetheha ea limolek'hule DNA amanang le liprotheine histone ba ntse ba ithuta. Ka mohlala, bafuputsi ba fumane hore chromatin fapaneng loci ba tšoanang chromosome maemo a fapaneng ba condensation. Ka mohlala, libakeng tse ikamahanya ho mitotic leakage radiation linaleli chromosome bitsoa centromeres, e teteaneng ho feta likarolo tse sa telomeric - qetellong loci.

Liphatsa tsa lefutso-balaoli le chromatin

Khopolo ea molao oa tsamaiso ea mosebetsi phatsa ea lefutso, a bōpa ke French geneticists Jakobo le Monod, fana ka e le maikutlo a ea ho ba teng ha libaka tse acid e deoxyribonucleic, eo ho eona ho na le boitsebiso bo mabapi le sebōpeho sa protheine le. Ba etsa feela bureaucratic - mmenejara mesebetsi. Reha lebitso liphatsa tsa lefutso balaoli, likarolo tsena tsa chromosomes hangata ka sebopeho lona bosula le bo-histone liprotheine. Chromatin, tlhaloso ea eona e ile etsoang ke hlahlamanya, e ile ea bitsoang bulehileng.

Ka lithuto tsa ka ho eketsehileng ho ile ha fumanoa hore ka loci tsena li fumaneha ka nucleotide tatelano hore thibela khomarela limolek'hule tsa DNA ea likaroloana protheine. likarolo tse ling joalo di na le dipegelo liphatsa tsa lefutso tse laolang ke: buellang ehansery activators. The compaction tsa chromatin ka ba phahameng, 'me bolelele ba likarolo tsena likarolelano ka 300 NM. Ho na le mokhoa ho beha skeletal bulehileng chromatin ka nuclei ka thōko tseo ho tsona ho sebelisa DNA-ase potlakisang tsebetso ea lik'hemik'hale. O ka potlako roba fatše loci ba chromosomes, a haelloa ke-histone liprotheine. Chromatin libakeng tsena 'nile la bitsoa hypersensitive.

Karolo e phethoang ke lefutso ntho

Mehahong ho akarelletsa le DNA, RNA le protheine e bitsoang chromatin, ameha ontogeny sele le ho fetola sebopeho lona ho itšetlehile ka mofuta o le dinama tse nyenyane tse 'me ka ho ba sethaleng sa tsoelo-pele ea ntho e phelang ka kakaretso. Mohlala, ka lisele epithelial tsa letlalo liphatsa tsa lefutso tse kang ehanser le mohlohlelletsi thibetsoeng liprotheine repressors, 'me liphatsa tsa lefutso tsena taolo ka lisele secretory tsa epithelium mala le ba mafolofolo ba sebakeng seo ba chromatin bulehileng. Bo-rasaense, geneticists fumanoa hore ka karoloana ea DNA tse sa encode lihaha-'mele, boikarabello fetang 95% ea liphatsa tsa lefutso ea batho. Sena se bolela hore taolo phatsa ea lefutso e tse ling tse ngata ho feta ba bona ba ikarabellang bakeng sa tswakana tsa peptides. Selelekeleng mekhoa tse kang dita DNA le hlahlamanya lumelloa ho fumana hore na ke eng e chromatin, 'me ka lebaka leo, ho lekanya ho liphatsa tsa lefutso tsa botho.

Lithuto tsa chromatin ke ea bohlokoa libakeng tse joalo saense tse kang liphatsa tsa lefutso tsa botho le liphatsa tsa lefutso tsa bongaka. Ena e amanang le boemo ba sharply tse eketsehileng tsa ketsahalo e sa mafu a lefa - joaloka phatsa ea lefutso le chromosome. ba bonoa pele tsa syndromes tsena eketsa peresente ya weather forecasts ntle kalafo bona.