Ke seo chromosome? Beha ba chromosomes. A para ea chromosomes

Lefutso le dipharologano fa lintho tsa tlhaho le teng hobane chromosomes, liphatsa tsa lefutso, acid e deoxyribonucleic (DNA). Mabenkeleng le fetisetsa lesedi liphatsa tsa lefutso ka mokgwa wa liketane tsa nucleotides ka DNA. Le karolo efe ka ketsahalo ena ke ea liphatsa tsa lefutso e? ke chromosome ya ka dipehelo tsa phetiso ea litšobotsi lefa lefe? Likarabo tsa lipotso tsena li tla utloisisa melao-motheo ea sa tsoaneng e le ho se tšoane liphatseng tsa lefutso lefatšeng. Ho ea bohōleng bo itseng ho itšetlehile ka hore na chromosome haholo kena sete, ho tswa ho recombination mehaho tsena.

From historing ea qalang ea "lefutso phatsa"

Ho ithuta ka tlas'a ya microscope ho lisele tse ea limela le liphoofolo, botanists ba bangata le zoologists ntse bohareng ba lilemo tsa bo-XIX, o ile a lebisa tlhokomelo ho dikgwele botle ka ho fetisisa le ho nyenyane ka ho fetisisa annular sebopeho ka khubung ea. hangata ho feta chromosomes tse ling bitsoa le pula-maliboho oa Jeremane anatomist Walther Flemming. E ne e le eena ea ileng a ba sebelisa aniline lidae bakeng sa lokisa mehaho ea nyutlelie. Fleming a sibolla ntho e bitsoang "chromatin" bakeng sa matla a hae a ho staining. Poleloana e reng "chromosome" ka 1888 ebandaki ka phetoho e khōlō ea saense Genrih Valdeyer.

Ka nako e tšoanang Flemming neng a se batla e le karabo ea potso ea hore na ke chromosome, e Belgian Édouard Van Beneden. Nakoana pele ho moo e Jeremane setsebi sa baeloji Theodor Boveri le Eduard Strasburger khanna letoto la liteko tse pakang hore na chromosomes, le tiisetso ea palo ea bona ka ho mefuta e fapaneng ea lintho tse phelang.

Background chromosomal khopolo ea lefutso

American Setsebi Walter Sutton fumana chromosomes bakae fumanoa motheo seleng. Scientific lumela dibopeho tsena bajari diyuniti tsa lefutso, litšobotsi tse 'mele. Sutton fumanoa hore chromosomes bopilwe liphatsa tsa lefutso, eo ka eona a fetisoa ho tloha ho batsoali ho litloholo tsa thepa le mesebetsi. Sa liphatsa tsa lefutso ka har'a lingoliloeng tse hlalositsoeng le chromosome bobeli, mokhatlo oa bona nakong ea petsoha ha khubung seleng.

Ho sa tsotellehe hore basebetsi-'moho le ea American, ho sebetsa ka tsela e tšoanang o ile a etella Theodor Boveri. Bobeli bafuputsi ba ka mesebetsi e ithuta litaba tsa phetiso ea litšobotsi lefa, rerileng litokisetso tsa motheo tsa ka karolo e phethoang ke chromosomes (1902-1903). ntshetsopeleng eketsehileng khopolo Boveri-Sutton etsahetse ka laboratoring ea Nobel hapileng Thomas Morgan. Phahameng American setsebi sa baeloji le sehlopha sa hae ba thehile letoto la melao ea tsamaisa liphatsa tsa lefutso tse chromosome ea, re ba le motheo oa cytological bakeng sa ho hlalosa mochine oa melao ea Gregor Mendel - ntat'a thehoeng ha liphatsa tsa lefutso.

The chromosomes ka seleng

Dipatlisiso tsa sebōpeho sa chromosomes o ile a qala ka mora ho sibolloa le tlhaloso ea lekholong la lilemo la XIX. Tsena nyenyane le linaleli tse phelang prokaryotic (bao e seng tsa nyutlelie) le lisele tse eukaryotic (ka khubung ea). Ho ithuta ka tlas'a ya microscope ho senola hore chromosome ke ntlha morphological maikutlo. Sena selefouno filamentous 'mele, e leng e bonahala ka mekhahlelo e itseng ea potoloho ea seleng. Moqolo eohle ea interphase khubung chromatin ae phethang. Ka linako tse ling distinguishable chromosome ka chromatids le 'ngoe kapa tse peli.

Molemo bone lihlopha tsena nakong karohano seleng e - mitosis kapa meiosis. Liseleng eukaryotic hangata e ka boloka chromosomes kgolo ya sebopeho guttate. Ka prokaryotes, ba nyenyane, le hoja ho na le ntle le mabaka a. Lisele tse hangata e kenyeletsa mofuta fetang e mong oa chromosomes, mohlala nyane bona "likaroloana lefa la" e mitochondria le chloroplasts.

foromo chromosomes

E mong le e chromosome e na le sebōpeho sa motho ka mong, e fapaneng ho tloha litšobotsi tse ling tse staining. Ho ithuta phetoho ke habohlokoa ho bona hore boemo ba centromere e, bolelele le bewa ga matsoho a lekanyelitsoeng ho thekeng ho ea. E behiloeng ea chromosomes hangata entsoe ka mekhoa e latelang:

• metacentric kapa-lekana, tšoauoa ka sebaka se bohareng ba centromere ea;
• submetacentric kapa neravnoplechie (constriction e koala ikutloeleng mong oa telomers);
• acrocentric, kapa molamu e bōpehileng joaloka, eo ho eona centromere e teng hoo e ka bang qetellong ea chromosomes;
• ba supa ka sebopeho hang definable.

chromosome mosebetsi

Chromosomes li entsoe ka liphatsa tsa lefutso - the diyuniti tsa tshebetso tsa lefutso. Li-telomere - ea lipheletsong tsa matsoho chromosome. likarolo tsena khetheha sebeletsa bakeng sa ho itšireletsa khahlanong le likhechana senya, antiblock. Centromere etsa mesebetsi lona le palopedi tsa chromosomes ena. E na le kinetochore, ke eena mounted sebopeho leakage radiation. E mong le e para ea chromosomes ke motho ka sebaka sa moo centromere ena. Linaleli sebetsa leakage radiation e le hore lisele tsa morali oa fetela ka chromosome e mong, empa ha bobeli. Junifomo palopedi mosebetsing oa ho fission fana ka tšimoloho ea boikatiso. Kopitsa ea e mong le chromosome e qala ka nako libakeng tse 'maloa joalo hore haholo eketsa tshebetso oohle oa ho arola.

Karolo e phethoang ke DNA le RNA

Ho fumana hore na ke eng e chromosome, e leng mosebetsi wa sebopeho sena tsa nyutlelie o ile a hlōleha ka mor'a ho ithuta ho hlophisoa lona skeletal le thepa. Liseleng eukaryotic, chromosomes tsa nyutlelie li thehoa ka lintho tse bonahalang fused - chromatin. Ho latela and analysis, ho na le lintho tse phahameng limolek'hule boima manyolo:

• asiti Deoxyribonucleic (DNA);
• asiti ribonucleic (RNA);
• histone liprotheine.

acid Nucleic ba nka e le karolo e tobileng ka biosynthesis ea-amino acid le liprotheine tse fanang ka phetiso ea litšobotsi tse lefa ho tloha molokong ho isa molokong. DNA tse motheo ea lisele eukaryotic, RNA e concentrated cytoplasm ena.

liphatsa tsa lefutso

X-ray and analysis ile a bontša hore DNA e bopa e spiral habeli, e akarelletsa ho ketane ea nucleotides. Ba emela k'habohaedreite deoxyribose, phosphate sehlopha le e mong oa makalana a mane nitrogenous:

1. A - adenine.
2. G - guanine.
3. T - thymine.
4. C - cytosine.

Lots dezoksiribonukleoproteidnyh helical linaleli - ka liphatsa tsa lefutso jereng lesedi coded ka tatelano ea-amino acid ka liprotheine kapa RNA. Nakong katiso ea litšobotsi tse lefa le tsoang ho batsoali ho bana e fetisoa ka mokgwa wa alleles phatsa ea lefutso. Ba beha tshebetsong, khōlo le tsoelo-pele ea itseng phelang. Ho ea ka bafuputsi ba bang ba, ba libakeng tsa DNA tse sa encode polypeptides phetha mesebetsi taolo. The liphatsa tsa lefutso tsa botho ka 'na na le liphatsa tsa lefutso ho fihlela ho 30 tse sekete..

beha ba chromosomes

Palo yohle ya chromosomes, libōpeho tsa bona - tšobotsi e khethollang la mokgwa. Ka fofa Drosophila palo ea bona - 8, ka litsoene - 48, motho - 46. Palo ena ke ea kamehla bakeng sa lisele tsa lintho tse phelang tse matleng a mefuta e tšoanang. Bakeng sa eukaryotes tsohle ho na le khopolo ea "chromosomes diploid phase." Ena sete e tletseng, kapa 2n, ho fapana le haploid - halofo palo (n g).

Chromosomes li entsoe ka para e 'ngoe ea homologous sebopeho tšoanang, sebopeho, sebaka, centromeres,' me likarolo tse ling. Homologues na le litšobotsi tse ba bona hore khetholla ho tloha chromosomes tse ling ka sete ena. Staining le lidae mantlha re lumella hore re ho nahana ka, hlahloba litšobotsi tse ikhethang tsa e mong le e para. chromosomes diploid phase se teng ka somatic lisele tse haploid tšoanang - ka kokoana-hloko (seo ho thoeng ke diretswe go dira gametes). Ka liphoofolo tse anyesang le lintho tse ling tse nang le heterogametic ho kopanela liphate e motona thehoa mefuta e 'meli ea chromosomes ho kopanela liphate: X chromosome le Y. batona ba le sete ya XY, tšehali - XX.

Batho chromosome sete

batho lisele tsa 'mele e na le 46 chromosomes. Kaofela ha bona ba kopanngoa ka lipara 23 tse etsang sete. Ho na le mefuta e 'meli ea chromosomes autosomes le ho kopanela liphate. Pele foromo 22 lipara - ke ho tloaelehile hore ho basali le ho banna. Di tšoauoa ka ba babeli ba 23 - ho kopanela liphate chromosomes, e leng lisele tsa 'mele e motona tse bao e seng homologous.

litšobotsi tse liphatseng tsa lefutso tse amanang le tekano. Bakeng sa phetiso ya di Y le X chromosome ka ba batona, ba babeli X basali. Autosomes na le ba bang kaofela ba boitsebiso bo mabapi le litšobotsi tse lefa. Ho na le mekhoa eo ho dumella ho motho ka nosi lipara tsohle 23. Ba hantle bonahalang ka lipalo, ha penta ka mmala itseng. Ho bonahala hore 22-chromosome tsa liphatsa tsa lefutso tsa botho - e nyenyane ka ho fetisisa. DNA lona le boemong otlolotse o e-ba bolelele ba 1.5 cm, le e na le lipara tse limilione tse 48 tsa makalana nitrogenous. Special liprotheine histones tloha chromatin ho phetha compression, 'me joale e ntan'o ba thread nka sebaka makhetlo a likete tse ka tlaase ho moo ka khubung seleng. Tlas'a e elektrone ya microscope, ho histones ka khubung interphase tšoana lifaha strung ka Strand ea DNA.

mafu a liphatsa tsa lefutso

Ho na le tse fetang tse likete tse tharo. Mefuta e sa tšoaneng ea mafu a lefa le bakoang ke ho senyeha le meferefere ka chromosomes ena. Tsena li akarelletsa Down syndrome. Bakeng sa ngoana ea nang le lefu le sa liphatsa tsa lefutso tšoauoa ka lieha ka ntshetsopeleng kelellong le 'meleng. Ka cystic fibrosis ho na le hore o hlōlehile ka mesebetsi ya litsoelesa exocrine. Tlōlo isang mathata le ho fufuleloa, ho lokolloa le ho bokella mucus 'meleng. E etsa hore ho be thata ho sebetsa matšoafo ho ka etsa hore le mathata ho hema le lefu.

Tlōlo ea pono mmala - bofofu - maloetseng ho likarolo tse itseng tsa 'mala a manyenyane. Hemophilia isang fokolisa ya hoama ea mali. Lactose mamellane ha a lumelle 'mele oa motho ho silehe tsoekere lebese. Ka liofising tsa thero ea malapa e ka fumanoa ka predisposition ho lefu le itseng liphatseng tsa lefutso. Litsing kgolo ya kalafi na le monyetla oa ho fumana sekasekale loketseng le kalafo.

Gene phekolo - tataiso ea moriana ea kajeno, elucidation ea bakang liphatsa tsa lefutso tsa mafu a lefa le ho ntsha lona. Le mekhoa ea morao-rao ka lisele tse pathological sebakeng sa khathatseha laolwa liphatsa tsa lefutso e tloaelehileng. Tabeng ena, lingaka li ba ne ba sa imolla mokuli matšoao, le mabaka a ho lefu lena. Khalemelo e phethahatsoa feela somatic seleng ea phatsa ea lefutso phekolo e sa leha ho le joalo massively sebelisoa mabapi le lisele ho kopanela liphate.