Umjikelo yeseli, sifo, iseli imvulophu

Ubukho nexesha iseli ukusuka kumhla lasungulwa ngokwahlula iseli unina ku hlula yayo okanye ukufa kuthiwa igama elithi "umjikelo iseli". Xa ixesha iseli ezahlukeneyo zalo ezahlukahlukeneyo. Umzekelo, carcinomas hematopoietic izihlunu emathunjini amancinci kunye sangaphandle bayakwazi ukuya kungena kumjikelo iseli emva kweeyure 12-16, bakhawuleza zande ubukhulu eziphilayo abadala. Mfutshane Kuyabonakala iiseli yokugqibela malunga nemizuzu engama-30, ukuba zenzeke ngexesha lokutyunyuzwa ngokukhawuleza amaqanda eziphila emhlabeni nasemanzini, echinoderms kunye nezinye izilwanyana. Inani elikhulu kweentlobo kwiimeko zovavanyo iseli inkcubeko, umjikelo zeeseli ixesha analo lifutshane malunga nemizuzu engama-20. Xa isixa eyinhloko ngokubonakalayo hlula ixesha iiseli ubude phakathi mitoses uvela iiyure ezili-10 ukuya kuma-24.

Amanqanaba kunye namaxesha kumjikelo cell. Umjikelo Iseli lezilwanyana kunye nezityalo iquka lwamathuba ezimbini: interphase (ixesha protein amagama kunye DNA) kunye mitosis (iseli umjikelo division). Interphase iquka ixesha ezininzi:

1. G1-phase - ixesha lokukhula, apho Yindibanisela iiprothini, RNA kunye nezinye abameleyo cell.

2. S-isigaba - kule lokuphumla kwenzeka lenjini interphase yale nkampani ye zinemoletyhule DNA ye eziba iseli kunye ukuphinda-organelles intracellular (centrioles);

3. G2-phase - ixesha apho kukho ukulungiselela mitosis.

Xa iiseli ukuba akukho kuphinda yahlula, G1-isigaba kungangabikho, kweli xesha, ukuba kwisigaba yokuphumla (G0).

Inkqubo candelo iseli (mitosis) iye izigaba ezimbini:

1. Ulwahlulwa-iseli ngumongo - mitosis.

2. Ulwahlulwa-iseli kukho icytoplasm - cytokinesis.

Ulawulo umsebenzi cell. Tshintsha lamathuba zomjikelo iseli kwenzeka xa unabanye iiprothini - cyclins kunye cyclin-oxhomekeke kinases. Iiseli kwi G0 ngezigaba ekwaziyo ngokungena ndzhendzheleko phantsi kweempembelelo imiba eyahlukeneyo ukukhula. Epidermal, yaye izinto zegazi-impiriyali ukuba luvo factor ukukhula, ezo xa zidibene rhoqo kunye receptors eziqhutywa inkqubo kweesiginali intracellular ekhokelela noshicilelo iiprothini sofuzo. Xa kinases efanayo inokuba esebenzayo kuphela intsebenziswano kunye cyclins ezithile, umxholo leyo esoloko itshintsha kulo mjikelo.

Ukuphazamiseka ummiselo eziqhelekileyo zomjikelo iseli ekhokelela ukuyilwa yamathumba eqinileyo. Kuba ukuyilwa yamathumba elinobuhlungu neprothini p53 unembopheleleko: uyayivuselela iproteni Yindibanisela p21, nto leyo abangaphangeliyo i CDK cyclin oluxandileyo, ekugqibeleni kukhokelela iseli umjikelo ngo G1 kunye kwisigaba G2. Iseli ne DNA eyonakeleyo akayi kungena S. Ngethuba lesigaba kohlo- ekhokelela ilahleko okanye ukutshintshwa gene protein p53 lungenzeki ngokuzenzekela kwaye nomjikelo iseli yaye kuvalwe kungena mitosis, isishiya iiseli njengesi, ezinye zazo zixheliwe, kwaye enye inxalenye ekhokelela ukuyilwa ebulalayo ngamathumba.

Cell-mediated nezifo. Indlela ukuba umxokomezelo wokugonyeka nayiphi isivuseleli, ebizwa omzimba apho izilwa azikho iseti inxaxheba kwaye nentsonkothileyo iiprothini ezikhoyo egazini (inkqubo ngumphelelisi), ebizwa ngalo igama elithi "sifo eyiselula". Oku kakhulukazi nxamnye ezincinane ephila ziiphagocytes nanxamnye amagciwane ezosulela ezinye iiseli. Ingakumbi kuyaphumelela nxamnye iintsholongwane, nomngundo, lenyama, iintsholongwane, kunye neeseli ithumba. inkqubo zeselula omzimba kubaluleke kakhulu kwezihlunu ukwaliwa.

Iseli eludongeni. Udonga iseli engqongqo, ibekwe umphandle inwebu cytoplasmic eyenza ukhuseleko, imisebenzi zokusebenza kunye kwezothutho - lelona ndizayo cell. Sekunjalo, le nto kuthiwa udonga iseli, oko ekhona ezininzi iintsholongwane, umngundo, izityalo kunye archaea. Njengokuba izilwanyana, kwaye uninzi elula, abanayo udonga iseli.