Ukuqonda ukuba i-zygote ihluke kwii-gametes, kufuneka umntu kuqala azi zonke iinkcazo zawo.
I-gamete yiseli yokuzala ephethe isethi enye (okanye i-haploid) yeema-chromosomes ezithatha inxaxheba ekuveliseni ngesondo. Oko kukuthi, ngamanye amazwi, iqanda kunye ne-spermatozoon yi-gametes eneesethi ze-chromosomes ezingama-23 nganye.
I-Zygote yiphumo le-fusion yeigetes ezimbini. Oko kukuthi, i-zygote yenziwa ngenxa ye-fusion yeqanda lomfazi kunye nesidoda sesilisa. Ngenxa yoko, ivela kumntu ngamnye (kwimeko yethu, umntu) kunye neempawu zobomi zabazali bobabini.
Sisiphi isethi se-chromosomes esenza i-zygote?
Njengoko kuyacaca, iisethi ze-chromosomes kwi-zygote zenziwe ngenxa ye-fusion ye-23 i-chromosomes nganye kwi-gametes yabazali, kuba i-zygote ngokwayo iyakhiwe ngexesha lokuhlanganiswa kwamagetetti amabini. Okokuthi, kukho i-chromosomes ezingama-46 kwi-zygote.
Indima ye-zygote kunye ne-gametes iphakamileyo, kuba ngaphandle kokuvelisa kwaye ukuguqulwa kwesizukulwana akunakwenzeka. Ukongezelela, ukubunjwa kwe-zygote kunye nophuhliso olulandelayo lwezilwanyana ezintsha kwi-zygote lunikeza ukuhlukahluka kofuzo lwabantu emhlabeni.
AmaGetet (iiseli zesini) avela kunoma yiyiphi na, kubandakanywa nomntu, umzimba emva kobutshatsha. Ezi iiseli zinikwe imisebenzi ekhethekileyo. Bathumela ulwazi lwelifa kwisizukulwana kwisizukulwana. I-nuclei yabo iqulethe zonke iinkcukacha eziyimfuneko kwilifa layo ngumbutho omtsha.
Ukuba sicinga ngamacandelo e-gametes abesilisa kunye nabasetyhini, banokungafani. Ngaloo ndlela, iqanda liqulethe i-cytoplasm eninzi kunye nezinto ezisondlo (i-yolk) eziyimfuneko ukuphuhliswa okuqhelekileyo kwebhokisi elizayo. Kwidimbini, ngokuchaseneyo, kukho umlinganiselo ophezulu we-vascular-cytoplasmic, okokuthi, phantse yonke iseli imelwe yinucleus. Oku kungenxa yomsebenzi oyintloko wesidoda - kufuneka ahambise izinto ngokukhawuleza kunokwenzeka kwiqanda.