Mibvunzo Yemuenzaniso Kukurukura Kuumbwa kweChromosomes muEukaryotic Nucleus
Maumbirwo echromosome chinhu chakakosha mu biology yemasero, zvichipa ruzivo rwekuti ruzivo rwemajini runochengetwa sei, runopfuudzwa sei, uye runoratidzwa sei mu eukaryotes. Muchinyorwa chino, tichatsanangura pfungwa huru dzemaumbirwo echromosome mu eukaryotic nucleus uye tichakupa mienzaniso yematambudziko nemhinduro kuti zvikubatsire kunzwisisa.
Nhanganyaya yeChromosome Structure muEukaryotic Nucleus
Machromosome maumbirwo akaita setsvimbo ari mukati menucleus yemasero eukaryotic. Anoumbwa neDNA nemapuroteni anonzi histones. Maumbirwo aya anoita basa rakakosha mukuona kuti ruzivo rwemajini rwakanyorwa nemazvo uye rwunogarwa nhaka panguva yekupatsanurwa kwemasero. Mukati memachromosomes, DNA inopetana uye inokombamira kutenderedza mahistones, ichiumba maumbirwo anozivikanwa senucleosomes. Manucleosome aya anowedzera kupetana nekupetana kuti aumbe chromatin yakakora, kunyanya panguva yekupatsanurwa kwemasero.
Maumbirwo Akadzama eChromosomes
1. DNA neNucleotides: DNA ine cheni refu yemanucleotides anoumba gene code. Manucleotides ane deoxyribose sugar, phosphate group, uye imwe yemabase mana ane nitrogenous: adenine (A), thymine (T), guanine (G), uye cytosine (C).
2. MaHistone: Mapuroteni aya anoshanda se "makoiri" anotenderedzwa neDNA. Kune mhando shanu dzemahistone dzinobatanidzwa mukuumbwa kwenucleosome: H1, H2A, H2B, H3, uye H4.
3. Nucleosome: Ichi ndicho chikamu chikuru chekurongeka kwema chromosome, chine chikamu chipfupi cheDNA chakaputirwa ne histone core.
4. Chromatin: Manucleosome anodzokorora anoungana pamwe chete kuti aumbe chimiro chinozivikanwa sechromatin. Chromatin inowanikwa mumhando mbiri: heterochromatin (yakakora uye isingashande) uye euchromatin (yakareruka uye inoshanda mukunyora).
5. Sister Chromatids: Kana DNA replication ikaitika, chromosome yega yega inogadzira makopi maviri akafanana anozivikanwa se sister chromatids, ayo akabatana pakati nechimiro chinonzi centromere.
Mibvunzo yemuenzaniso nehurukuro
Mubvunzo 1:
Tsanangura musiyano mukuru uripo pakati pechromatin nemachromosomes.
Kukurukurirana:
Chromatin nemakromosomu marudzi maviri akasiyana ezvinhu zvemajini zvinobatanidzwa mukugara nhaka. Chromatin imhando yeDNA isina kurongeka uye isina kuumbwa iripo panguva yechikamu chepakati pechikamu chesero, zvichibvumira mukana wekunyora nekudzokorodza DNA. Kusiyana neizvi, makromosomu imhando yakapfupikiswa yechromatin inoonekwa panguva yemitosis nemeiosis; izvi zvinoita kuti zvinhu zvemajini zvigoverwe zvakanaka kumasero emwanasikana. Chaizvoizvo, musiyano mukuru uri muhuwandu hwekukonzeresa uye kushanda panguva yesero.
Mubvunzo 2:
Maumbirwo ehistone anokanganisa sei kurongedza kweDNA munucleus yemasero eukaryotic?
Kukurukurirana:
MaHistones anoita basa guru mukurongedza nekuronga DNA mukati menucleus yesero. DNA ine chaji isina kunaka (nekuda kwephosphate), nepo mahistones aine positive zvakanyanya nekuda kwehuwandu hwayo hwakawanda hwe lysine ne arginine. Kubatana uku kunobvumira DNA kutenderera zvakasimba pakati pehistone, zvichigadzira chimiro che nucleosome. Pasina mahistones, DNA refu, isina kusimba yaizonetseka kuvapo mumasero, tisingatauri nezvekushanda zvinobudirira. MaHistones anogonawo kugadziriswa nemakemikari (akadai se acetylation uye methylation), izvo zvinokanganisa kugona kweDNA kunyora nekukopa.
Mubvunzo 3:
Basa re centromere mukupatsanurwa kwemasero nderei uye nei richikosha?
Kukurukurirana:
Centromere chikamu chakakosha chechromosome chinoshanda senzvimbo yekubatanidza mapuroteni chaiwo anonzi kinetochores panguva yekupatsanurwa kwemasero. Kinetochores inzvimbo dzekubatanidza ma microtubule fibers ane basa rekudhonza ma chromatids echikadzi kuenda kumatanda akatarisana e sero rinoparadzanisa. Nzvimbo chaiyo ye centromere uye kuumbwa kwekinetochore kunoshanda zvakakosha pakupararira kwema chromosome zvakanaka uye kudzivirira aneuploidy, mamiriro ezvinhu umo masero ane nhamba isina kujairika yema chromosome, izvo zvinogona kutungamira kuzvirwere zvemajini.
Mubvunzo 4:
Sei euchromatin ichionekwa seinokosha mukunyora kupfuura heterochromatin?
Kukurukurirana:
Euchromatin inoonekwa seinonyanya kukosha mukunyora nekuti chimiro chayo chakasununguka kupfuura heterochromatin, zvichiita kuti ma enzymes ekunyora asvike nyore nyore kuDNA. Basa guru reeuchromatin nderekuratidza majini anodiwa pakushanda kwemasero kwezuva nezuva. Kusiyana neizvi, heterochromatin inowanzova nemajini asingashande kana kuti asingadiwi nguva dzose uye anoramba akamanikana kudzivirira kunyora. Chaizvoizvo, euchromatin inzvimbo ye genomic inoshanda zvakanyanya mukunyora.
Mubvunzo 5:
Kugadziriswa kwehistone kunokanganisa sei kuratidzwa kwemajini? Ipa muenzaniso weimwe yekuchinja uku.
Kukurukurirana:
Kugadziriswa kweHistone kunogona kukanganisa kuratidzwa kwemajini nekuchinja chimiro chechromatin uye kugona kwemajini kumashini ekunyora. Muenzaniso mumwe chete ihistone acetylation, umo boka reacetyl rinowedzerwa kune lysine residue iri pamuswe wehistone. Kugadziriswa uku kunoderedza simba rakanaka rehistone, kunopedza simba rekudyidzana pakati pehistones neDNA, uye kunoguma nechimiro chechromatin chakavhurika. Izvi zvinowedzera kugona kweDNA kune transcription factors uye RNA polymerases, nokudaro zvichiwedzera kugona kwegene.
Mhedziso
Kunzwisisa maumbirwo uye mashandiro emakromosomu mumasero eukaryotic kwakakosha pakutsvagurudza kwepamusoro mu molecular biology uye genetics. Dambudziko iri rekukurukurirana rakagadzirirwa kuwedzera kunzwisisa kwevadzidzi nevaongorori nezvekuti zvipenyu zvinochengeta nekuronga sei ruzivo rwemajini, uye kuti shanduko muchimiro ichi dzinogona sei kubatsira muzviitiko zvakasiyana-siyana zvezvipenyu nezvirwere.
