Ukuphendula kungukuphindaphindiwe: iseli kusuka kuseli

Ukungabaza ngokubunjwa kwamakhophi amabili afanayo - isenzakalo esijwayelekile ngempela ohlelweni lwezinto eziphilayo. Ngokuvamile ukuphindaphinda okunjalo kubizwa ngokuthi ukuphindaphinda. Lokhu kungase kwenzeke emazingeni ahlukene enhlangano yendaba - kusuka ku-DNA ngqo kuma-chromosomes namaseli aphelele. Kule nkinga, uma inqubo idlule ngokungaphumeleli, kutholakala amayunithi amabili afanayo. Ukuziphendulela kuyigugu lokuphinda ngokuphindaphindiwe.

Njenganoma ikuphi kwenye indawo

Okuthakazelisayo kakhulu futhi okuyisisekelo kuzo zonke ezinye izinhlobo yi-DNA replication. Le nqubo eyenzeka ngezigaba eziningana, okuyiwona nalowo okubaluleke kakhulu, ngoba ukungalungi kuyothuthukisa ukuhlanganiswa kwamaprotheni angalungile, okungafanelekile ukusetshenziswa esitokisini nasemzimbeni wonke.

Qala kokuqala

Ukuphindaphinda kweselula kuqala ngokuphindaphindiwe kwe-DNA, eneziphumo zokuphindaphinda ama-chromosomes. Kodwa ukuphindaphinda kuyisisekelo sezinhlelo zonke. Iqukethe izinyathelo ezintathu: okokuqala, ukuqala, kwesibili, ukuphakanyiswa kwesithathu, nokwesithathu, ukuqedwa. Umsebenzi we-enzyme uqala ngamaphuzu akhethekile - izimpendulo kanye kuphela. Ukuqala endaweni engafanele kungaphazamisa inqubo yonke. I-enzyme-catalyst ivuselela amaprotheni akhethekile abumba isakhiwo sokuphindaphinda esadingeka ukuze kutholakale i-DNA kabili. Ngaphambi kokuzalana, i-DNA ihlukaniswe izingxenye ezimbili nama-enzyme akhethekile.

Ikhampasi Ephelele

Lapho kuphakanyiswa kwe-matrix, ukwakhiwa kokubeletha komama kuhlanganiswa. Yilokho, owodwa ngaleso sikhathi ongakha i-molecule ehlanganisiwe. Le nqubo iphela ngokuqedwa, okwenzeka futhi endaweni ethile. Kukhona iyunithi ekhethekile - i-replicon. Leli fragment le-DNA elakhiwa ngesikhathi. Ukuphindaphinda kwe-DNA yisisekelo, ngaphandle kokuphindaphinda kwe-chromosome akunakwenzeka. Lokhu kwenzeka uma iseli lilungiselela ukuhlukaniswa.

Amaprotheni njengendlela

Ukuphindaphindiwe kwe-chromosome kuqala ngemva kwamahora ngemva kokuphindaphindiwe kwe-DNA. Ukuze sakhe kabusha i-chromosome, asidingi kuphela amasethi amasha we- deoxyribonucleic acid, kodwa futhi namaprotheni ayingxenye yezinto zokusebenza ze-chromosome, futhi ukuthatha isikhathi kuthatha isikhathi. Ukuphindaphinda ngokushesha kuyisibonakaliso somdlavuza. Uma kutholakala amaprotheni amaningi, isici sokuhlukaniswa kwamaseli amakhulu , udokotela uqala ukukhala i-alamu.

Isikhala sanele

Kukhona isici esithakazelisayo enkambisweni yokuphindaphinda - esikhaleni esiyisisekelo, amaphuzu okuqala we-DNA amasha ahlelwe ngendlela efanele, ngakho-ke akukho ukuphazamiseka okungabangela ithonya elilodwa. Kukhona amachashazi amaningi, njengombuso, owodwa nengxenye kuya kwambili.

Indlela ama-chromosome azohlelwa ngayo incike ekutheni i-mitosis noma i-meiosis ivele yini esitokisini. Esikhathini sokuqala esitokisini esakhiwe kuyoba nesethi evamile, engxenyeni yesibili. Phela, isigamu esisele sizoletha iseli lomlingani wesibili ekuzalweni kocansi. Uma, nge-meiosis, isethi ephelele itholakele ngokuzumayo, iseli lesidakamizwa ngeke likwazi ukuguquka, noma ukukhulelwa komntwana ogulayo kuzokwenzeka. Kodwa-ke, izingane ezinjalo zivame ukuzalwa, kukhona ukukhulelwa kwesisu ekuqaleni kokukhulelwa, okungenzeka ukuthi umama angathatha ukuphuma kwenyanga noma kwe-ovulatory phakathi nomjikelezo.