Umjikelo wobomi iiseli - ixesha ukususela ekuzalweni kwayo ukuya kwicandelo okanye ukufa elizimeleyo

Umjikelo wobomi iiseli - ixesha yunithi eziziziqalelo nabaphilayo ukususela ekusekweni kwayo ukuya kwisahlulo yalo hlula okanye ukufa. Oku kuquka zonke iinguqu zendalo ezilandela organelles ekuqhubeni imisebenzi yayo.

Ngokuxhomekeke umbutho kunye nomgangatho ezikhethiweyo umjikelo wayo iseli unokuthatha kwi imizuzu engama-30 neentsuku ezi-3. Ngokomzekelo, xa ezityumza iiseli echinoderms umjikelo wobomi banemizuzu engama-30, yaye sangaphandle emathunjini abantu - ngeeyure ezili-12. Kukho abo iiyunithi ezisisiseko zokuphila, nto leyo wahlulelana yedwa, oko kukuthi, musa ziyazala, ke enza umsebenzi yabo kwezo baze bafe - .. afana luvo, iifayibha izihlunu striated. Self lomjikelo wobomi iseli lungohlulwa lube iiphiriyodi ezimbini: interphase, okanye ithuba lokukhula kunye mitosis - division xesha. Interphase ibandakanya, ngokulandelelana, kwiqela lezigaba:

1. G1 (postmitotic) - kwisigaba sokuqala ukukhula. Kweli nqanaba, ibandla mRNA, iiproteni kunye namanye amacandelo cell.
2. S (chemicals) - kwenzeka DNA phindana, nto leyo ekhokelela ukuba ukuphinda-genetic material. Ekupheleni kwesigaba amabini DNA kweleli efanayo kabini. Ngamnye kwiindawana ka deoxyribonucleic acid iqulathe omnye siba ubudala, kwaye eyesibini - entsha, leyo kwakheka kwi sisiseko complementarity.
3. G2 (premitotic) - yinkqubo yokulungisa, ebandakanya nokulungisa iimpazamo ezenziwa ngexesha DNA kudibaniso kwisigaba odlulileyo. Angemi izondlo, amandla, qhubeka nokulungelelanisa iiprothini kunye RNA.

Into engundoqo ke olukhutshelweyo umjikelo mitotic of iseli proliferative okanye eqala ngqo emva G2. It is a iseti iinkqubo kwenzeka kwiyunithi aphantsi noshowo aphilileyo, iphuma candelo elinye ukuya kwelinye icala kwaye enze isizukulwana esitsha weeseli ancedisayo. Mitosis na uhlobo olungundoqo sisahlula somatic (hayi inxaxheba ukuzala) iiyunithi eziziziqalelo eziphilayo zenyukliya.

Umjikelo wobomi iiseli ukuze umzimba, ukubonelela ukhuseleko inani kunye nemilo zofuzo uphawu kweentlobo (karyotype) ngamnye, ngoko ke kubalulekile ukuba onke amathuba ukwahlukana sele kudlule ngaphandle kokuphazanyiswa. Mitosis ubunjwe ngezigaba 4 ezilandelelanayo:

1. Prophase. Ngeli xesha, iyantlukwano iseli kwenzeka kwaye ukungangqinelani phakathi centrioles izibonda, apho amaqhina oqhagamshelwano phakathi yi ukwahlukana yokuluka. Ekupheleni kweli thuba nucleoli iba chromosome eqinileyo kwaye asisifutshane, ngamanye i amafu yabo.
2. Metaphase. isakhiwo Nucleoprotein elungelelaniswe iiseli ikhweyitha kwakhiwa metaphase nembasa. Kuza constriction ephambili zofuzo. Emva koko, ngamnye kubo yahlulwe chromatids ezimbini.
3. Anaphase. Kwesi sigaba obrazovashiesya zofuzo intombi bafudukela nezibonda ezahlukeneyo, apho tyaba uze uzive uhlazi- yekile.
4. Telophase. Walibuyisela nucleolus kunye icandelo undoqo kukho icytoplasm kwenzeka.

Ngenxa yoko, umjikelo iseli - ixesha lobomi ukususela ekuzalweni ukuya unit eziziziqalelo kokufa abaphilileyo.