Maumbirwo eChromosome muZvipenyu Zvipenyu
Machromosome ndeimwe yezvinhu zvakakosha mumasero mapenyu nekuti anoshanda se "mudziyo" mukuru weruzivo rwemajini. Machromosome ane DNA, ine majini anodzora hunhu, mashandiro emuviri, uye kukura kwechisikwa kubva musero rimwe chete kusvika kumunhu akazara. Maumbirwo emachromosome anonakidza kwete chete nekuda kwechimiro chawo asiwo nekuti akagadzirwa sei, akarongwa sei, uye akagara nhaka sei. Kunzwisisa maumbirwo emachromosome kunotibatsira kutsanangura zviitiko zvakawanda zvehupenyu, kubva pakugara nhaka kwehunhu nekukura kusvika kuzvirwere zvemajini.
Kunzwisisa ma chromosomes nebasa rawo
Kazhinji, machromosomes maumbirwo akafanana neshinda anowanikwa munucleus yesero (muzvisikwa zveeukaryotic), anoumbwa neDNA neprotein. Muzvisikwa zveprokaryotic zvakaita sebhakitiriya, zvinhu zvemajini hazviwanikwe mukati menucleus yesero asi zvakarongwa muchimiro chechromosome imwe chete kana zvimwe zvinhu zvakati wandei zveDNA zvakatenderera.
Mabasa makuru emachromosomes ndeaya:
1. Inochengeta ruzivo rwemajini muchimiro cheDNA sequences.
2. Inodzora kuratidzwa kwemajini, kureva kana majini ari kushanda kana kusashanda.
3. Inovimbisa kugoverwa kwakakodzera kwezvinhu zvemajini kana masero akapatsanuka (mitosis nemeiosis).
4. Kupfuudza hunhu kubva kuvabereki kuvana vavo.
Nemamwe mashoko, machromosome anogona kufungwa nezvawo senzira yakarongeka zvikuru yekunyora nekutarisira ruzivo rwezvehupenyu.
Zvikamu zve chromosome: DNA ne protein
Machromosome anoumbwa nemacomplex eDNA nemapuroteni, kunyanya mapuroteni ehistone. DNA imorekuru refu rine ruzivo rwemajini kuburikidza nenhevedzano yemabases ane nitrogen (A, T, G, C). Zvisinei, DNA refu yakadaro haigone kungo "siyiwa" munucleus diki yesero. Nokudaro, DNA inofanira kurongedzwa zvakanaka.
Apa ndipo panonyanya kukosha basa rema histones. Mapuroteni e histone anoita se "spools" iyo DNA inosungirirwa. Musanganiswa uyu weDNA nemapuroteni unonzi chromatin. Maumbirwo e chromatin anoshanduka: pasi pemamwe mamiriro ezvinhu, zvinoreruka kubvumira kunyorwa kwemajini, nepo pasi pemamwe mamiriro ezvinhu, zvinova zvishoma kuchengetedza DNA uye kuita kuti chromosome ipatsanurwe panguva yekupatsanurwa kwemasero.
Kuwanda kweDNA mu chromosomes
Maumbirwo echromosome haasi "tambo yeshinda" chete, asi mugumisiro wemaitiro ekuisa DNA muzvikamu zvakawanda. Muchidimbu, matanho ekurongedza anosanganisira:
1. DNA ine denderedzwa remadenderedzwa maviri
DNA idenderedzwa remadenderedzwa maviri rine dhayamita inosvika 2 nm. Ichi ndicho chimiro cheDNA.
2. Nucleosome
DNA yakaputirwa nepuroteni sere dzehistone kuti igadzire chinhu chinonzi nucleosome. Chimiro chayo chinowanzo fananidzwa ne "mabheya ari patambo." Nucleosomes dzakakosha pakuumbwa kweDNA pakutanga.
3. Chromatin faibha
Manucleosome anobva abatana zvakasimba, zvichiita kuti DNA iite chromatin fibers yakakora. Kurongedza uku kunowedzera huwandu hweDNA kuti ikwane mukati menucleus yesero.
4. Zvidimbu zveChromatin nemadhomini
Matinji eChromatin anoumba maumbirwo akasungirirwa pachimiro cheprotein munucleus. Kurongeka kwezvitenderedzwa izvi kunokanganisa zvakanyanya kuwanikwa kwemajini uye, nokudaro, kwakabatana nekudzora kutaurwa kwemajini.
5. Machromosome akapfupikiswa
Kana sero rava kuda kupatsanurana, chromatin inoungana zvakasimba kuti igadzire machromosome, ayo anoonekwa zvakajeka pasi pemaikorosikopu ine chiedza. Ichi ndicho chimiro che "X" chatinowanzoona mumabhuku ebiology, kunyange zvazvo chinonyanya kuonekwa panguva yechikamu chemetaphase chekupatsanurana kwemasero.
Kurongedza uku kwemazinga akawanda kunoratidza kuti chimiro chemakromosomu hachisi nyaya yechimiro chete, asiwo nzira yehupenyu yekugadzirisa mashandiro eDNA.
Zvikamu zvikuru zvemachromosomes
Machromosomes anoonekwa zvakajeka panguva yekupatsanurwa kwemasero ane zvikamu zvakakosha zvakati wandei:
1. Masisita emachromatids
Mushure mekudzokororwa kweDNA, chromosome inoumbwa nemakopi maviri akafanana anonzi ma chromatids ehanzvadzi. Ma chromatids maviri aya anopatsanurwa panguva yekupatsanurwa kwemasero kuitira kuti sero rega rega riwane kopi yakafanana yeDNA.
2. Centromere
Chikamu checentromere chikamu chakamanikana chinobatanidza ma chromatids echikadzi. Nzvimbo iyi inoumba chimiro cheprotein chinonzi kinetochore, uko spindle fibers dzinobatana panguva yekupatsanurwa kwemasero. Nzvimbo yecentromere inosarudzawo chimiro chechromosome.
3. Ruoko p na q
Machromosome ane maoko maviri: ruoko rupfupi runonzi p (petit) uye ruoko rurefu runonzi q. Kupatsanurwa uku kunobatsira pakuongorora majini uye kuona kusarongeka kwema chromosome.
4. MaTelomere
MaTelomeres "mavharo" ari kumagumo emachromosomes anoumbwa neDNA sequences dzinodzokororwa. Basa rawo nderekudzivirira magumo emachromosomes kubva mukukuvadzwa uye kudzivirira DNA kuti isabatwa sezvidimbu zvinoda kugadziriswa. MaTelomeres anoitawo basa mukukwegura kwemasero uye kugadzikana kwemajini.
5. Chromatin: euchromatin uye heterochromatin
– Euchromatin yakasununguka, ine majini akawanda anoshanda, uye inonyorerwa zviri nyore.
– Heterochromatin yakakora, kazhinji majini haashande zvakanyanya, uye inoita basa rakakosha mukugadzikana kwechimiro chema chromosome.
Kusiyana kwechimiro chekromosome zvichienderana nenzvimbo ye centromere
Nzvimbo ye centromere inokanganisa chimiro che chromosome. Kazhinji, kune mhando dzakasiyana-siyana:
– Metacentric: centromere iri pakati, maoko ese ari maviri akaenzana pakureba.
– Submetacentric: centromere inoshandurwa zvishoma, maoko haana kureba kwakafanana.
– Acrocentric: centromere iri pedyo nemagumo, ruoko rumwe rupfupi zvikuru.
– Telocentric: centromere iri kumagumo chaiko (inowanikwa zvakanyanya mune dzimwe mhuka, isingawanzoitika muvanhuwo zvavo).
Kupatsanurwa uku kwakakosha muzvidzidzo zve cytogenetic, kunyanya pakuona shanduko dzemaumbirwo akadai sekuchinjirwa kwemasero kana kubviswa kwemasero.
Machromosome muvanhu nezvimwe zvipenyu
Rudzi rumwe nerumwe rune nhamba yaro yemachromosome. Vanhu vane machromosome makumi mana nematanhatu mumasero emuviri (2n), ane ma autosome makumi maviri nemaviri uye ma chromosome maviri ebonde (XX kana XY). Ma Gametes (masero embeu nemazai) ane hafu yenhamba iyoyo, ma chromosome makumi maviri nematatu (n), nekuda kwe meiosis.
Huwandu hwemachromosomes hahuwanzoenderana zvakananga ne "danho rekuomarara" kwechisikwa. Mimwe miriwo ine machromosomes akawanda kupfuura vanhu. Izvi zvinogona kunge zvichikonzerwa ne polyploidy (kudzokororwa kwemaseti emachromosome), izvo zvakajairika mumiti uye zvinobatsira mukusiyana kwemarudzi nekushanduka-shanduka.
Mumabhakitiriya, machromosomes anowanzova molecule imwe chete yeDNA yakatenderera. Kunyangwe zviri nyore, mabhakitiriya achiri neDNA yakaputirwa nemapuroteni chaiwo uye nzira dzinovimbisa kudzokororwa kwakakodzera uye kugara nhaka.
Kuchinja kwechimiro chemakromosomu uye simba razvo
Maumbirwo echromosome anogona kuchinja zvinhu zvichikonzera shanduko yemajini kana kusashanda zvakanaka. Dzimwe shanduko dzinowanzo dzidzwa dzinosanganisira:
– Kubviswa: kurasikirwa kwechikamu chemakromosomu.
– Kudzokorora: kudzokororwa kwezvikamu zvekromosomu.
- Kuchinja: zvikamu zvekromosome zvinodzokera shure munzira.
– Kutamiswa: chikamu chinoenda kune chimwe chromosome.
Kuchinja uku kunogona kuva kudiki, kusina kwakarerekera, kana kwakakomba, zvichienderana nezvikamu zvinobatanidzwa. Muvanhu, kusarongeka kwemakromosomu kunogonawo kusanganisira kuchinja kwenhamba (semuenzaniso, trisomy), asi kuchinja uku munhamba kwakabatana zvikuru nekukamurwa kwemakromosomu panguva yemeiosis, pane chimiro chawo chemuviri.
Penutup
Maumbirwo emachromosomes muzvinhu zvipenyu anoratidza kusimba kwemaitiro ekuchengetedza ruzivo rwezvinhu zvipenyu. Kubva paDNA helix diki kusvika kumachromosome akapfupikiswa anoonekwa panguva yekupatsanurwa kwemasero, zvese zvakarongeka nenzira yakarongwa uye yakarongeka. Machromosomes haangodziviriri DNA chete asiwo anotonga kushandiswa kwemajini uye anovimbisa kugara nhaka kweruzivo rwemajini. Kunzwisisa maumbirwo emachromosome kunovhura nzira yekunzwisisa mashandiro ekutanga ehupenyu, ukuwo zvichibatsira mushonga ne biotechnology mukuona nekurapa zvirwere zvakasiyana-siyana zvemajini.
Kana muchida, ndinogona kuwedzera chikamu chakatsaurirwa pamusoro pemusiyano wemakromosomu muprokaryotes vs eukaryotes, kana kugadzira shanduro yechinyorwa chinotarisa zvakanyanya pamakromosomu evanhu uye kusarongeka kwemakromosomu.
