Mene ne chromatin: definition, sifa da aiki

Biochemical karatu a jinsi - wata muhimmiyar hanya zuwa karatu ta babban aka gyara - genes kuma chromosomes. A wannan labarin, za mu dubi abin da yake chromatin, gano ta sifa da aiki a cikin cell.

Gadar hali - babban dũkiyar rai al'amari

Daga cikin babban matakai cewa faye hali kwayoyin da cewa rayuwa a duniya, suna numfashi, da abinci, da girma, da kuma zabin haifuwa. A karshe aiki ne mafi muhimmanci da adana rayuwa a wannan duniya tamu. Yaya ba tuna cewa umarnin farko da aka ba da Allah da Adamu da Hauwa'u ya da wadannan: "Ku hayayyafa ku riɓaɓɓanya." A matakin na sel generative aiki aka yi da nucleic acids (bijiro da batun kafa abu na chromosomes). Wadannan Tsarin za a tattauna a abin da ya bi.

Mun kuma ƙara da cewa adana da kuma watsa kayyade bayanai ɗauke da zuriyar guda inji cewa ba ya dogara ne a kan matakin kungiyar na mutane, cewa shi ne don cutar da kwayoyin cuta, da kuma shi ne na kowa da kowa da mutane.

Mene ne abu na gadar hali

A cikin wannan takarda mun yi nazarin chromatin tsarin da kuma ayyuka na waxanda suke tsaye dogara a kan kungiyar na nucleic acid kwayoyin. Swiss masanin kimiyya Miescher a 1869 mahadi da aka gano a cikin nuclei na sel na rigakafi da tsarin, exhibiting Properties na acid kira su da farko nukleina sa'an nan nucleic acid. Daga mahangar sunadarai, shi macromolecular fili - polymers. Wadannan monomers ne nucleotides da ciwon da wadannan tsarin: a purine ko pyrimidine tushe, da kuma pentose saura na orthophosphoric acid. Masana kimiyya sun gano cewa nau'i biyu daga nucleic acid na iya zama ba a cikin Kwayoyin: DNA da RNA. Suna complexed tare da sunadarai ta samar da wani fili na chromosomes. Kazalika da sunadarai, nucleic acid da mahara matakan sarari kungiyar.

A 1953 da Nobel Prize ya Watson da Crick deciphered tsarin DNA. Yana da wani kwayoyin hada da sarƙa biyu juna da hydrogen shaidu tasowa tsakanin nitrogenous sansanonin kan qa'ida ta complementarity (m adenine taimain tushe located gaban saitosin - Bibyun). Chromatin sifa da aiki da abin da muke karatu, da kwayoyin qunshi wani deoxyribonucleic acid da kuma ribonucleic daban-daban jeri. A wannan batun, mun tattauna a more daki-daki a cikin sashe "Matsayin chromatin kungiyar."

Sarrafawa daga cikin abu na gadar hali a wani cell

DNA ba a cikin wadannan cytostructure matsayin da zuciyar, da kuma a wasu gabbansa, iya division - mitochondria da chloroplast. Wannan shi ne saboda cewa wadannan da wasu gabbansa yi da muhimmanci ayyuka a cikin cell: ATP kira, da kuma kira na glucose da oxygen samuwar a shuka Kwayoyin. Roba da wasu gabbansa taka iyaye ninkininki lifecycle. Saboda haka, ya Kwayoyin a mitosis (rarraba somatic Kwayoyin) ko meiosis (samuwar maniyyi da kuma ova) afforded da ake so arsenal cell Tsarin samar da Kwayoyin tare da gina jiki da kuma samar da makamashi.

Ribonucleic acid kunshi daya sarkar da kuma yana da ƙananan kwayoyin nauyi fiye da DNA. Ta samu duka a cikin tsakiya da kuma a hyaloplasm, kuma shi ne wani ɓangare na da yawa kwayoyin halitta: ribosomes, mitochondria, endoplasmic reticulum, plastids. Chromatin a wadannan gabbai a hade da histone da furotin da kuma wani ɓangare na plasmids - madauwari rufaffiyar DNA din.

Chromatin tsarin da kuma

Saboda haka mun tabbatar da cewa nucleic acid kunshe ne a cikin dũkiyar chromosomes - tsarin raka'a gadar hali. Su chromatin ta na'urar hange yana da nau'i na granular ko filamentous Tsarin. Ya ƙunshi, kuma da DNA, kuma ko da RNA kwayoyin, da kuma sunadarai exhibiting asali Properties kuma suna histones. Duk na sama Tsarin wani bangare ne na nucleosome. An same su a cikin nucleus din da chromosomes ake kira fibrils (thread-solenoids). Taƙaita dukan sama, mun sanin cewa wannan chromatin. Wannan hadadden fili na deoxyribonucleic acid da kuma takamaiman sunadaran - histones. Su, kamar coils, suna rauni biyu-stranded DNA din ya samar da wata nucleosome.

Matsayin chromatin kungiyar

gadar hali abu yana da wani daban-daban tsarin, wanda ya dogara a kan al'amurra da dama. Alal misali, a kan abin da mataki na rayuwa sake zagayowar jurewa cell: rarraba lokaci (metoz ko meiosis), ko roba presynthetic a lokacin Interphase. Daga cikin wani nau'i na solenoid, ko fibrils, kamar yadda mafi sauki, akwai gaba compaction na chromatin. Heterochromatin - a mafi m jihar, aka kafa a cikin intron rabo daga cikin chromosome, wanda ba zai yiwu kwafi. A lokacin da sauran Kwayoyin - Interphase, a lokacin da babu wani rabo aiwatar - heterochromatin karyoplasm located a cikin nucleus din peripherally, a kusa da membrane. Sealing nukiliya abinda ke ciki postsynthetic mataki na faruwa a cikin rayuwar sake zagayowar na sel, Ina nufin nan da nan kafin division.

Abin da kayyade sandaro na al'amari na gadar hali

Ci gaba da bincike da tambaya "abin shi ne chromatin," masu bincike gano cewa, shi ya dogara da hatimi-histone sunadaran da cewa, tare da kwayoyin na DNA da RNA a nucleosome. Sun kunshi hudu nau'o'in sunadaran, da ake kira shanu da kuma linker. A lokacin da ya kwafi (karanta na bayanai daga gene via RNA) gadar hali abu talauci Fused, kuma aka kira euchromatin.

A halin yanzu musamman rarraba DNA din ya hade da histone sunadaran da ake yi karatu. Alal misali, masu bincike gano cewa, chromatin daban-daban loci na wannan chromosome daban-daban matakan sandaro. Alal misali, a wuraren da abin da aka makala ga mitotic dogara sanda chromosome filaments kira centromeres, shi ne mafi m fiye da telomeric sassan - karshen loci.

Kwayoyin halittu-gwamnoni da kuma chromatin

A ra'ayi na da tsari na gene aiki, halitta da Faransa jinsi Yakubu da Monod, ba wani tunani na kasancewar yankunan deoxyribonucleic acid, a cikin abin da babu wani bayani game da tsarin da gina jiki. Sun yi zalla ba komai haqqinsa - kociya ayyuka. Ambata sunayen kwayoyin halittu gwamnoni, wadannan sassa na chromosomes yawanci a cikin tsarin bã tãre-histone sunadaran. Chromatin, da definition wanda aka za'ayi da jerawa, aka mai suna bude.

A kara nazarin an gano cewa, a wadannan loci suna located a nucleotide jerin cewa hana riko da DNA kwayoyin gina jiki barbashi. Irin wannan rabo dauki kashi dokokin genes ne: promoters ehansery activators. A compaction na chromatin cikin su ne high, da kuma tsawon wadannan sassan Averages game da 300 nm. Akwai hanya domin kayyade biochemical bude chromatin a ware nuclei a cikin abin da amfani da DNA-ase enzyme. Ya sauri karya saukar loci na chromosomes, rasa-histone sunadaran. Chromatin a cikin wadannan yankunan da aka kira hypersensitive.

Rawar da gadar hali abu

Gidaje ciki har da DNA, RNA da kuma gina jiki kira chromatin, da hannu a cell yanayin halitta na juya da kuma canza abun da ke ciki dangane da nama irin da a kan mataki na ci gaba da kwayoyin a matsayin dukan. Msl, a cikin epithelial Kwayoyin na fata irin kwayoyin halittu kamar yadda ehanser da kuma kiran kasuwa katange sunadaran repressors, kuma wadannan dokokin genes a cikin secretory Kwayoyin na hanji epithelium da suke aiki a yankin na bude chromatin. Masana kimiyya, masana auren gano cewa, a wata sulusi da murabba'i na DNA da cewa ba encode sunadarai, lissafin kudi don a 95% na mutum genome. Wannan yana nufin cewa gene iko ne sosai fiye da wadanda suke da alhakin kira na peptides. A gabatarwar da dabaru irin DNA kwakwalwan kwamfuta da jerawa yarda ka gano abin da chromatin, kuma a sakamakon, domin shata kan mutum genome.

Nazarin na chromatin ne mai muhimmanci a irin wannan wurare na kimiyya, kamar mutum halittar jini da kuma likita itatuwa aure. Wannan ake dangantawa da wani sharply ya karu matakin na abin da ya faru na hereditary cututtuka - kamar gene da kuma chromosome. Farkon ganewa na wadannan syndromes qara yawan m kintace a magani.