Yintoni i-zygote, zeziphi iimpawu zayo kunye nophuhliso

Ukuze uqonde indlela inkqubo yokuchumisa kunye nokuzalwa kobomi obutsha eyenzekayo, kuyimfuneko ukuziqonda ngeengcamango ezisisiseko. Kubalulekile ukuqonda ukuba yiyiphi i-zygote. Kwaye ukuba uphendule eminye imibuzo malunga nendlela eyakhelwe ngayo, yiyiphi impawu ekhethekileyo enayo, zeziphi izigaba zokuphuhliswa kwayo, oko kunokukuthintela.

Ngoko, masiqale kwasekuqaleni, ngempendulo kumbuzo wokuqala. Yintoni i-zygote? Le selesi, eyenziwa njengesiphumo sefestile ezimbini zesini zomzali kwinkqubo ebizwa ngokuba yi-fertilization. Yimpawu yezinto ezingezizo zesini, kwaye ziyabandisa. Ukuphila kwezinto eziphilayo, apho zakhiwa khona izityalo, azikho abantu kunye nezilwanyana kuphela, kodwa nezityalo ezininzi kunye nezifungulu. Eli thuba lenziwe ngu-sayensi-botanist waseJamani E. u-Strasburger ekupheleni kwekhulu le-19.

Xa siqonde ukuba yintoni i-zygote, makhe sikhumbule oko iiseli eziyifumayo zibonakaliswe ngayo. Amaseli ezesondo, okanye iigetet, ziveliswa ngamalungu akhethekileyo (ngokwesondo), apho ubukho bendawo enye (haploid) yeema -chromosomes bubunjani. Njengoko sele siyiqonda, ukubunjwa kwe-zygote kwenzeka ngenxa yemanyano yamagetetti amabini, oko kuthetha ukuba iqukethe idijithi (idilogidi) isethi yezinto zeDNA. Isisele esicacileyo esinika umgangatho omtsha, ngcaciso yenzululwazi, ikhona. Oko kukuthi, inako ukuvelisa ngokupheleleyo nayiphi na iseli yomzimba. Yintoni enye into enomdla malunga nale sakhiwo seselula? I-Zygote yahlula ekuqaleni ayifuni iseli eqhelekileyo. Ngaphambi kwamacandelo akukho nqanaba lokukhula, kwaye ekugqibeleni iiseli zentombi nganye ezalandelayo ziya kuba ziincinci kunezidlulileyo. Ngenxa yesiphumo esilandelayo, iqanda le- fetal lifana ne-mulberry berry.

Ukuba sicinga yonke inkqubo yokuphuhliswa kwebribho yonke, ngoko singayiphendula umbuzo wento ye-zygote, ngolu hlobo lulandelayo. Ngenye yezigaba zokuphuhliswa kwayo. Isigaba sokuqala sithathwa njengegetet, kwaye izigaba ezalandelayo sele zibonakalise ukutshintshwa okulandelelanayo kwi-zygote. Yile ndlela amaqela alandelelana ngayo ahlukeneyo emkhatsini. Isigaba esilandelayo emva kokuba i-zygote i-morula (akukho sakhiwo ekubunjweni), ilandelwa yi-blastula (i-embryo ene-single-layered embryo), i-gastrula (i-embryo enezintathu), kwaye ekugqibeleni, i-neurula ehamba ngokugqithiseleyo ibe yi-organogenesis.

Ngendlela, sibona iphuzu elimnandi: isigaba se-zygote sesilwanyana esiphilayo siyakudlulela. Oku kwenzeka kumakhowa kunye ne-algae. Emva kokuchumisa kunye nokwakhiwa kweseli ye-diploid, iya kuba yindawo yokuphumla kwaye ihlala ixesha elide. Kule meko, eli selesi libizwa ngokuba yi-zygospora. Kubantu, ixesha eliphumayo liphela iiyure ezingama-30 kuphela. Ngeli xesha, i-embryo ezayo ihamba kunye ne-tube fallopian ngaphakathi kwesibeleko, apho emva kwithuba elithile, ukutshalwa kweqanda lomntwana kwi-mucosa kwenzeka. Ukugqithiswa kwenkqubo eqhelekileyo yale nkqubo kunye nokuphuhliswa okuqhubekayo kwe-zygote kunokubangelwa zizinto ezintle ezifana nokuguqulwa kwamanqanaba athile okanye i-chromosomes epheleleyo, ukusetyenziswa kotywala ngumfazi, izidakamizwa zamachiza, imithi ethile, ukutshaya kunye nezifo zentsholongwane.