Ixesha lesigaba ngasinye yomjikelo weseli: indlela yobugcisa kunye nokungathathi hlangothi.
Intshayelelo kumjikelo weseli
El umjikelo weseli Yinkqubo inzima kwaye ilawulwa kakhulu evumela ukuveliswa kunye nokukhula kweeseli. Kuwo wonke lo mjikelo, iiseli zihamba kuluhlu lwezigaba ezahlukeneyo apho iintlobo ezahlukeneyo zemisebenzi zenzeka khona, njengokuphindaphindwa kwe-DNA kunye nokwahlulwahlulwa kweeseli. Qonda indlela esebenza ngayo umjikelo weseli Kubalulekile ukuqonda iinkqubo zebhayoloji ezisisiseko, ezinjengophuhliso, ukuphiliswa kwenxeba, kunye nomhlaza.
I-cell cycle yenziwe ngezigaba ezine eziphambili: isigaba se-G1 (i-Gap 1), isigaba se-S (i-Synthesis), isigaba se-G2 (i-Gap 2) kunye ne-M isigaba (i-Mitosis). Ngethuba lesigaba se-G1, iiseli zikhula kwaye ziqhube imisebenzi yayo eqhelekileyo. Kwinqanaba elingu-S, i-DNA iyaphindwa ukuze ilungiselele ulwahlulo lweeseli. Ngethuba lesigaba se-G2, iseli ilungiselela i-mitosis kunye nokukhula okungaphezulu kunye ne-protein synthesis. Ekugqibeleni, isigaba se-M sisigaba apho ukwahlukana kweeseli kwenzeka khona.
Ukulawulwa komjikelo weseli kubalulekile ukukhusela iimpazamo kwi-DNA yokuphindaphinda kunye nokwahlulwa kweseli okungalawulwayo. Kukho iiprotheyini ezithile, ezifana ne-cyclin-dependent kinases (CDKs), ezisebenza njengokutshintsha ukuqala okanye ukumisa izigaba ezahlukeneyo zomjikelezo weseli. Ngaphezu koko, umjikelo weseli udityaniswe ngokusondeleyo neendlela zokulungisa i-DNA, ezenza kube lula ukulungisa nawuphi na umonakalo kwizinto zofuzo ngaphambi kokuphindaphinda kunye nokwahlulwa kweseli.
Iindidi zezigaba zomjikelezo weseli
Umjikelo weseli unezigaba ezininzi ezibalulekileyo apho iiseli ziyahlukana kwaye zivelise kwakhona. Ezi zigaba zahlulwe zaba ngamanqanaba ahlukeneyo, ngalinye lineempawu kunye nemisebenzi ethile. Okulandelayo, ndibonisa ezona ntlobo ziphambili zezigaba zomjikelo weseli:
-Inqanaba le-G1: Esi sigaba, esaziwa ngokuba sisigaba sokukhula, kulapho iseli ikhula kwaye ilungiselela ukuphinda-phindwa kwezinto zayo zemfuzo. Ngeli nqanaba, iseli iyanda ngobukhulu kwaye ivelise amacandelo ayimfuneko kwi-mitosis. Apha, ukuphindaphindwa kwee-organelles zeselula nako kwenzeka.
–Isigaba S: Isigaba S sibalulekile kumjikelo weseli, ekubeni kusebudeni beli nqanaba apho ukwakheka kweDNA kwenzeka. Ngesi sigaba, i-genetic material (i-chromosomes) iyaphindwa kwaye ikopi echanekileyo yechromosome nganye yenziwa. Le nkqubo ibalulekile ukuqinisekisa ukuba iiseli zentombi zinemathiriyeli yemfuza efanayo neyeseli kamama.
-Inqanaba le-G2: Emva kwesigaba se-S, iseli ingena kwisigaba se-G2, esaziwa ngokuba sisigaba sokulungiselela i-mitosis. Ngeli nqanaba, iseli iyaqhubeka ikhula kwaye ilungiselela ukwahlukana kweeseli. Ukongezelela, kuqinisekisiwe ukuba i-DNA iphindwe ngokuchanekileyo kwaye iimpazamo ezinokuthi zilungiswe ngaphambi kokungena kwisigaba esilandelayo.
Isigaba se-G1: Ixesha lokukhula kunye nolungiselelo lokuphindaphinda i-DNA
I-G1: Ixesha lokukhula kunye nokulungiselela uphinda-phindo lwe-DNA
Inqanaba le-G1 linyathelo lokuqala kumjikelo weseli, owaziwa ngokuba lixesha lokukhula kunye nokulungiselela ukuphindaphindwa kweDNA. Ngeli nqanaba, iseli lifumana ukukhula kunye nokwanda kobukhulu, ngaphezu kokwenza imisebenzi eyahlukeneyo ukuqinisekisa ukuphindaphinda kwe-DNA eyimpumelelo.
Kwinqanaba le-G1, iseli iqhuba ezi nkqubo zilandelayo:
- Ukwenziwa kweeprotheyini: Ngexesha lokukhula, iseli ivelisa iiproteni ezintsha eziyimfuneko ekusebenzeni nasekuphuhlisweni kwayo.
- Ukulawulwa komonakalo we-DNA: Iseli ihlala ihlola ukuba kukho nawuphi na umonakalo kwi-DNA kwaye, ukuba ifunyenwe, ivule iindlela zokulungisa okanye ibangele i-apoptosis (ukufa kweseli ecwangcisiweyo) ukuba umonakalo awunakulungiswa.
- Ukulungiselela ukuphindaphindwa kwe-DNA: Ngeli nqanaba, iseli ilungiselela ukuphindaphinda kwe-DNA, idibanisa amacandelo ayimfuneko kunye nokuqinisekisa ukuba zonke iimeko zilungele inkqubo. Oku kubandakanya ukuveliswa kwamandla kunye nokugcinwa, ukusetyenziswa kwe-enzyme, kunye nokuphindaphinda kwe-centrosome.
Isishwankathelo, isigaba se-G1 somjikelezo weseli lixesha elibalulekileyo ekuphuhlisweni kweeseli, apho ukukhula okunzulu kunye nokulungiselela ukuphindaphinda kwe-DNA kwenzeka. Ngokusebenzisa iprotein synthesis, ukulawula umonakalo we-DNA, kunye nokulungiselela amacandelo ayimfuneko, iseli iqinisekisa ukuba zonke iimeko zilungele ukuphindaphinda ngempumelelo. Emva kokuba isigaba se-G1 sigqityiwe, iseli ilungele ukuqhubela phambili kwisinyathelo esilandelayo somjikelezo weseli.
Ukubaluleka kwendawo yokukhangela i-G1
Indawo yokuhlola i-G1 yinxalenye ebalulekileyo yenkqubo yokulawula umgangatho wayo nayiphi na inkqubo. Le yimodyuli yokubeka iliso nokwalusa enoxanduva lokuqokelela kunye hlalutya idatha ngexesha langempela ukuqinisekisa ukusebenza ngendlela eyiyo kwenkqubo. Le ndawo yokukhangela ibalulekile ekuchongeni ukusilela okanye ukungahambi kakuhle okunokuthi kuchaphazele ukusebenza kwe-G1.
Enye yeenzuzo eziphawulekayo ze-G1 checkpoint kukukwazi ukuvelisa iingxelo ezicacileyo kunye nezichanekileyo malunga nobume benkqubo. Ezi ngxelo zinceda ekubhaqeni iintsingiselo kunye neepatheni zokuziphatha ezikuvumela ukuba wenze izigqibo ezizizo ukongeza ukusebenza kakuhle kwe-G1.
Olunye uphawu olubalulekileyo lwe-G1 yokukhangela ikhono lokuqwalasela ii-alamu kunye nezaziso ezilumkisa abasebenzi xa kunokwenzeka ukuba kubonwe iingxaki okanye kugqithwe imida ethile. Ngale ndlela, impendulo ekhawulezayo nesebenzayo iqinisekisiwe kuyo nayiphi na imeko efuna ingqalelo ngokukhawuleza.
Isigaba S: DNA synthesis
Isigaba S somjikelo weseli saziwa ngokuba yi "DNA Synthesis Phase" okanye "DNA Replication." Ngeli nqanaba, imathiriyeli yemfuza yeseli iyaphindwa, iqinisekisa ukuba iseli nganye yentombi inekopi epheleleyo nechanileyo yeDNA.
I-DNA synthesis iqala ngokwahlukana kwemisonto emibini ye-DNA kwi-molecule yokuqala. Nganye yale misonto isebenza njenge template yokwenziwa komcu omtsha oncedisayo. I-enzyme DNA polymerase idlala indima ebalulekileyo kule nkqubo, njengoko inoxanduva lokudibanisa ii-nucleotides ezichanekileyo kwikhonkco elitsha elikhulayo. Njengoko uphindaphindo luqhubela phambili, iimolekyuli ezimbini ezifanayo zeDNA ezingqinelana neyokuqala ziyenziwa.
Kubalulekile ukukhankanya ukuba isigaba se-S yinkqubo elawulwa kakhulu ukuphepha iimpazamo ekuphindaphindeni kunye nokugcina ingqibelelo ye-genome. Izinto ezifana nokufumaneka kwe-nucleotide, ukusebenza kweeprotheni zokulawula, kunye nokulungiswa kweempazamo zokuphindaphinda ziqinisekisa ukuba ikopi echanekileyo, esebenzayo yezinto zofuzo zenziwe kwiseli nganye yeentombi. Ngale ndlela, ukuhanjiswa okuchanekileyo kolwazi lwemfuza ukusuka kwesinye isizukulwana ukuya kwesinye kuqinisekisiwe.
Inkqubo yokuphindaphinda i-DNA kwisigaba S
Kwisigaba S somjikelo weseli, inkqubo ebalulekileyo eyaziwa ngokuba yi-DNA replication iyenzeka. Esi siganeko sibalulekile ukuze kuqinisekiswe ukugqithiswa okuchanekileyo kolwazi lwemfuza kwiiseli zeentombi ngexesha lokwahlulwa kweeseli.
Ukuphindaphinda kwe-DNA yinkqubo ye-semiconservative, okuthetha ukuba i-molecule ye-DNA yoqobo iyahlula kwaye isebenze njengethempleyithi yokudityaniswa komcu omtsha oncedisayo. Inkqubo iqala ngokukhulula i-DNA kabini i-helix ngenxa ye-helicase ye-enzyme. Emva kokuba i-strand ibonakalisiwe, i-DNA polymerase iya kwisenzo kwaye iqala ukudibanisa i-nucleotides ehambelanayo, ngaloo ndlela yenza i-DNA strand entsha.
Le nkqubo yophindaphindo yenzeka ngokuphindwe kabini kwiindawo ezibizwa ngokuba ziindawo zolwaluko lokuphindaphinda. Njengoko i-DNA polymerase ihamba ngeentambo ze-DNA, yenza amaqhekeza e-Okazaki kwi-strand eshiyekileyo. La maqhekeza emva koko adityaniswa yi-DNA ligase, nto leyo eyenza ukuba kubekho iimolekyuli ezimbini ezifanayo zeDNA. Ukuphindaphindwa kwe-DNA kwisigaba se-S yinkqubo elawulwa kakhulu kunye neyinkimbinkimbi eqinisekisa ukunyaniseka kolwazi lwemfuza kunye negalelo ekuqhubekeni kobomi.
Isigaba se-G2: Ukulungiselela ulwahlulo lweeseli
La fase Umjikelo weseli we-G2 Lixesha elibalulekileyo lokulungiselela ulwahlulo lweeseli. Ngeli nqanaba, iseli iqinisekisa ukuba onke amacandelo ayimfuneko akhoyo kunye nomthamo owaneleyo wokuqinisekisa ukuphindaphinda kwe-DNA eyimpumelelo kunye nokwahlulwa kweeseli ezilandelayo.
Kule nqanaba, iseli iqinisekisa ukunyaniseka kwe-DNA, iqinisekisa ukulungiswa kwawo nawuphi na umonakalo okanye iimpazamo kwi-DNA replication ngexesha le-S isigaba, kwaye inoxanduva lokulungisa nawuphi na umonakalo ofunyenweyo. Ukongeza, ukuphindaphindwa kwe-centrosomes, izakhiwo ezibalulekileyo zeselula zokuqinisekisa ukwahlula okuchanekileyo kweechromosomes ngexesha lokwahlula kweeseli, kuyenziwa.
Kukwisigaba se-G2 apho ukuhlanganiswa kweeprotheyini eziyimfuneko kwi-mitosis kwenzeka, njengeeproteni zeemoto ezivumela ukuhamba kweechromosomes ngexesha lokwahlukana kweeseli. Ukongeza, iseli ilungiselela i-cytokinesis, inkqubo apho i-cytoplasm yahlula ukwenza iiseli ezimbini zeentombi. Oku kubandakanya ukubunjwa kweringi yekhontrakthi eyenziwe nge-actin kunye ne-myosin filaments ekhontrakthi yokwahlula iiseli.
Ukufunyanwa kwezinto ezingaqhelekanga kwindawo yokukhangela ye-G2/M
Kwinkqubo yokwahlulahlula kweeseli, indawo yokukhangela i-G2/M ibaluleke kakhulu ukuqinisekisa ukwahlulwa okuchanekileyo kweechromosomes kunye nokuphepha ukubunjwa kweeseli zeentombi ezineempazamo zofuzo. Ukubona izinto ezingaqhelekanga kule ndawo yokuhlola kubalulekile ukuqinisekisa ukuthembeka kwezinto zofuzo kunye nokuthintela ukwanda kweeseli ezonakalisiweyo.
Kukho iindlela ezahlukeneyo kunye nezixhobo ezisetyenziswa kwi. Enye yazo i-flow cytometry analysis, evumela ukuvavanya umxholo we-DNA, ukwanda kweeseli kunye nobukho bokuguqulwa kwe-chromosomal. Ukongezelela, iimpawu ezithile zisetyenziselwa ukuchonga ukubonakala kweenguqu kwiijene eziphambili ezinxulumene nokulawulwa kokwahlula kweeseli.
Okubalulekileyo, ukufunyanwa kwangaphambili kwezinto ezingaqhelekanga kwindawo yokuhlola i-G2 / M kunokuba nefuthe elibalulekileyo ekuxilongweni nasekunyangweni kwezifo ezifana nomhlaza. Ngokusebenzisa iindlela zokubona ezikumgangatho ophezulu, kuyenzeka ukuchonga utshintsho lwemfuza kwangethuba kunye nokuyila amacebo onyango lomntu. Olu ngenelelo lokuqala lunokuphucula kakhulu iziphumo zeklinikhi kunye nokunyusa izinga lokusinda kwezigulane.
Inqanaba M: Ukwahlulwa kweeseli kunye nokwahlulwa kwechromosome
Isigaba se-M somjikelo weseli sisigaba esibalulekileyo kubomi beseli, apho ukwahlukana kweeseli kunye nokwahlulwa kwechromosome kwenzeka. Esi sigaba sahlulwe kwiinkqubo ezimbini eziphambili: i-mitosis kunye ne-cytokinesis.
Kwimitosis, iichromosomes eziphindaphindwayo zimi kumbindi weseli zize zohlulwe ngokulinganayo zibe ngamaqela amabini. Ukufezekisa oku, ii-microtubules ezibizwa ngokuba zii-achromatic spindles zenziwe ezincamathela kwiichromosomes kwi-centromere yazo. Ezi spindle, ngokuncipha kunye nobude bazo, zihambisa iichromosome kwindawo yazo echanekileyo kwiseli ngaphambi kokuba zohlulwe zibe ngamaqela amabini afanayo.
Emva kokuba iichromosomes zihlulwe ngokuchanekileyo, i-cytokinesis iqala. Kule nkqubo, iseli yahlulahlulwe ibe ziiseli ezimbini zeentombi ngokwenza i-constriction kwi-plasma membrane ebizwa ngokuba yi-cleavage furrow. Le constriction yenziwa ngenxa yokucutheka kweringi yeeproteni ezijikeleze iseli, ukwahlula icytoplasm kwaye yenze iiseli ezimbini zeentombi ezihluke ngokupheleleyo. Iseli nganye kwezi intombi ngoku inekopi epheleleyo, esebenzayo yemathiriyeli yemfuza eyimfuneko ekusebenzeni kwayo ngokufanelekileyo.
Inkqubo ye-mitosis kunye nokwakheka kweeseli zentombi
I-Mitosis yinkqubo apho iseli yoomama yahlulahlulwe ibe ziiseli zentombi ezimbini ezifanayo ngokwemfuza. Le nkqubo ibalulekile ekukhuleni, ekuphuhliseni nasekuveliseni izinto eziphilayo ezininzi. Izigaba ze-mitosis kunye nokwakheka kweeseli zeentombi zichazwe ngezantsi:
- Ujongano: Ngaphambi kokungena kwi-mitosis, i-stem cell idlula kwinqanaba lokulungiselela elibizwa ngokuba yi-interphase. Ngesi sigaba, iseli iphinda iphinda-phinda zombini imathiriyeli yemfuza kunye ne-organelles yayo, ukuqinisekisa ukuba iiseli zentombi ziya kuba nolwazi lwemfuzo olufanayo njengeseli yomama.
- Iprophase: Kweli nqanaba, iichromosomes ziyajiya kwaye zibonakale phantsi kwemikroskopu. I-nucleolus iyanyamalala kwaye amaqhekeza emvulophu yenyukliya. Ngaxeshanye, i-microtubules ye-cytoskeleton iqala ukwenza i-mitotic spindle, isakhiwo esiyimfuneko yokwahlula okuchanekileyo kweechromosomes kwiiseli zentombi.
- I-Metaphase: Ngesi sigaba, iichromosomes zilungelelaniswa kwi-equatorial plane, eyaziwa ngokuba yi-metaphase plate. Ikhromozomu nganye incanyathiselwe kwimitotic spindle ngokusebenzisa iicentromeres zayo kwaye ikukokuxina kwayo okuphezulu. Olu lungelelwaniso lubalulekile njengoko luqinisekisa ukuba iichromosomes zisasazwa ngokulinganayo phakathi kweeseli zeentombi kwisigaba esilandelayo.
I-Mitosis iyaqhubeka kunye nezigaba ze-anaphase kunye ne-telophase, apho ukuhlukana kunye nokwahlula kokugqibela kwe-chromosome kwenzeka, ngokulandelanayo. Ezi zigaba ziphetha nge-cytokinesis, inkqubo yokwahlulwa kwe-cytoplasm evelisa iiseli ezimbini zeentombi. Ngale ndlela, ukuqhubela phambili kwezinto zofuzo kunye nokukhula kwezinto eziphilayo ezininzi ziqinisekisiwe.
Indima ebalulekileyo yeendawo zokuhlola kwisigaba M
Kwinqanaba le-M lomjikelo weseli, iindawo zokukhangela zidlala indima ebalulekileyo ekuqinisekiseni ukuba ukwahlukana kweeseli kwenzeka ngokuchanekileyo. Ezi ndawo zokukhangela iindawo zolawulo ezivavanya ingqibelelo ye-DNA, indibano echanekileyo yamacandelo e-mitotic spindle kunye nokulungelelaniswa okuchanekileyo kweechromosomes. Ukuba kukho nasiphi na isiphazamiso esibhaqiweyo, ezi ndawo zotshekhiwo zimisa ukuqhubeka komjikelo weseli ukuvumela ukuba kulungiswe umonakalo okanye iimpazamo zilungiswe.
Indawo yokukhangela yokuqala kwisigaba se-M, esaziwa ngokuba yi-metaphase checkpoint, inoxanduva lokuqinisekisa ukuba zonke iichromosomes zilungelelaniswe ngokuchanekileyo kwi-equatorial plane yeseli. Ukwenza oku, iiprotheyini ezibizwa ngokuba yi-kinetochores zibandakanyeka, ezincamathela kwi-centromeres yeechromosomes kwaye zibambelele kwii-microtubules ze-mitotic spindle. Ukuba nayiphi na i-kinetochore ayiqhotyosheli ngokuchanekileyo okanye i-chromosomes ingahambelani kakuhle, imiqondiso yokumisa i-checkpoint ivuliwe, imisa ukuqhubela phambili kwi-anaphase de ukungaqhelekanga kusonjululwe.
Enye i-checkpoint ebalulekileyo kwisigaba se-M yi-checkpoint ye-anaphase. Umsebenzi wayo kukuqinisekisa ukuba ichromosome nganye yahlula ngokufanelekileyo kuzo zombini iipali zeseli ngaphambi kokwahlulwa kokugqibela. Xa i-kinetochores ihlula ngokuchanekileyo kwaye ii-microtubules zisebenzisa amandla afunekayo ukuqhuba ukuhlukana kwe-chromosome, i-checkpoint ivumela ukuba i-anaphase iqhubeke. Nangona kunjalo, ukuba kukho nasiphi na isitenxo esifunyenweyo, izibonakaliso zokumisa i-checkpoint zithintela iseli ukuba iqhubele phambili kwi-telophase kunye ne-cytokinesis, inika ixesha lokusombulula ingxaki kunye nokuphepha iimpazamo zofuzo.
Iziphumo zotshintsho kwizigaba zomjikelo weseli
Utshintsho kwizigaba zomjikelo weseli lunokuba neziphumo ezininzi emzimbeni, kuba le nkqubo ibalulekile ekukhuleni, ekuphuhliseni nasekugcinweni kwezicubu. Apha ngezantsi zezinye zeziphumo ezibalulekileyo ezinokuthi zenzeke xa izigaba zomjikelo weeseli zichaphazeleka:
Ukulahlekelwa kukukwazi ukuzilawula: Xa utshintsho lwenzeka kwizigaba zomjikelo weseli, iiseli zinokuphulukana namandla azo okuzilawula, oku kuthetha ukuba zinokuqala ukwahlukana ngokungalawulekiyo. Le nto, eyaziwa ngokuba yi-cell proliferation engalawulwayo, inokukhokelela ekubunjweni kwamathumba kunye nomhlaza.
Ukuwohloka kweDNA: Utshintsho kwizigaba zomjikelo weseli lunokukhokelela kumonakalo weDNA. Ngexesha lokuphindaphinda kweeseli kunye nokwahlula, iimpazamo zinokuthi zenzeke ekukhupheleni izinto zofuzo, ezibangela ukuguquka. Olu tshintsho lunokuguqula umsebenzi oqhelekileyo weeseli kwaye lube negalelo ekuphuhliseni izifo zofuzo okanye umhlaza.
Ukwaluphala kwangethuba: Esinye isiphumo sotshintsho kwizigaba zomjikelo weseli kukuguga kwangaphambili kwezicubu. Xa iiseli zingahluli ngokufanelekileyo kwaye zibe nomonakalo kwi-DNA yazo, inkqubo yokuguga iyakhawuleza. Oku kunokuzibonakalisa ekuwohlokeni kwesikhumba, iinwele kunye ne-immune system, kunye nokunciphisa umthamo wokuvuselela nokulungiswa kwezicubu.
Iingcebiso zophononongo kunye nokuqonda okuchanekileyo kwezigaba zomjikelo weseli
Ukulungisa into ngempumelelo Ukufunda kunye nokuqonda ngokuchanekileyo izigaba zomjikelo weseli, kubalulekile ukulandela ezinye iingcebiso eziphambili. Ezi zikhokelo ziya kunceda ekuqinisekiseni ukuba ufumana ulwazi oluqinileyo noluneenkcukacha ngale nkqubo isisiseko kwibhayoloji yeeseli.
1. Ziqhelanise nezinto ezisisiseko:
Ngaphambi kokungena kwizigaba ezithile zomjikelo weseli, kubalulekile ukuba ube nokuqonda okupheleleyo kweengqikelelo ezisisiseko. Qinisekisa ukuba uyawaqonda amagama angundoqo, afana ne-mitosis kunye ne-meiosis, kunye nezakhiwo kunye nemisebenzi yee-organelles eziphambili zeselula ezibandakanyekayo kumjikelo weseli.
2. Sebenzisa izixhobo ezibonakalayo:
Izigaba zomjikelo weseli zinokuntsonkotha ukuze ube nombono ngokufunda kuphela. Ukuququzelela ukuqonda, sebenzisa izixhobo ezibonakalayo ezifana nemizobo, imizobo kunye neemodeli ezintathu-dimensional. Ezi zixhobo ziya kukuvumela ukuba ubonise ngokucacileyo nangokuchanekileyo umahluko amanqanaba omjikelo weseli kunye nendlela ezinxibelelana ngayo.
3. Yenza izenzo kunye nemifuniselo:
Eyona ndlela ingcono yokomeleza ulwazi lwakho malunga nezigaba zomjikelo weseli kukusebenzisa oko ukufundileyo. Yenza iimvavanyo ezilula, usebenzisa i-microscopes kunye neenkcubeko zeeseli, ukujonga ngokuthe ngqo izigaba ezahlukeneyo zomjikelezo weseli ekusebenzeni. Ukongeza, ziqhelanise nokuphendula imibuzo ekhethiweyo kunye nokusombulula iingxaki ezinxulumene nesi sihloko ukomeleza ukuqonda kwakho kunye nokuphucula izakhono zakho zokuhlalutya.
Izigqibo malunga nexesha lesigaba ngasinye somjikelezo weseli
Emva kohlalutyo olucokisekileyo, ezinye izigqibo zinokuthathwa malunga nobude besigaba ngasinye somjikelezo weseli. Ezi zigqibo zisisiseko ukuqonda inkqubo yokwahlulwa kweeseli kunye nolawulo lwayo.
Okokuqala, kunokuchazwa ukuba isigaba se-G1 sesona sigaba siguquguqukayo kakhulu ngokwexesha laso. Esi sigaba sibalulekile ekukhuleni kweeseli kunye nokuhlanganiswa kweeprotheyini eziyimfuneko ekuphindaphindeni i-DNA. Nangona kunjalo, ubude besigaba se-G1 sinokuchaphazeleka ngezinto ezahlukahlukeneyo ezifana nokufumaneka kwezondlo, ubukho bokukhula kwamaselula okanye iimpawu zokuthintela, kunye nokuphendula kwezinto eziphilayo kwi-stimuli yangaphandle.
Ngakolunye uhlangothi, isigaba se-S, apho uphindaphindo lwe-DNA lwenzeka khona, luhlala luhlala luhlala ixesha elide. Ngesi sigaba, iiseli ziphinda-phinda imathiriyeli yemfuzo ukuqinisekisa ulwazi oluchanekileyo lwemfuzo kwiiseli zentombi. Ubude besigaba se-S ngokuqhelekileyo bufana neentlobo ezahlukeneyo zeeseli kwaye azichatshazelwa ngokuthe ngqo kwizinto zangaphandle okanye zangaphakathi.
Okokugqibela, isigaba se-G2, esandulela ulwahlulo lweeseli, sikwabonisa ixesha elingaguqukiyo kwiiseli ezininzi. Ngesi sigaba, iseli ilungiselela ukwahlulwa kwe-DNA ngokudityaniswa kweeprotheyini kunye nokuphinda-phindwa kwee-organelles eziyimfuneko ekwenzeni iiseli zentombi. Nangona kukho iinguqu kwixesha lesigaba se-G2, ezi ngokubanzi zihambelana nohlobo lweeseli kwaye azichatshazelwa zizinto ezibalulekileyo zangaphandle.
Imibuzo neempendulo
Umbuzo: Liliphi ixesha lesigaba ngasinye somjikelo weseli?
IMPENDULO: Ixesha lesigaba ngasinye somjikelo weseli libhekiselele kwithuba elithile kwinqanaba ngalinye lomjikelo weseli kwinto ethile ephilayo.
Umbuzo: Zeziphi izigaba zomjikelo weseli?
A: Umjikelo weseli uqukethe izigaba ezine eziphambili: isigaba se-G1 (isigaba sokukhula 1), isigaba se-S (i-DNA synthesis), isigaba se-G2 (isigaba sokukhula 2), kunye nesigaba se-M (isigaba sokwahlula).
Umbuzo: Liliphi ixesha eliphakathi kwisigaba ngasinye somjikelo weseli?
A: Ixesha eliqhelekileyo kwisigaba ngasinye somjikelo weseli linokwahluka ngokuxhomekeke kuhlobo lweseli kunye nezinto eziphilayo ekuthethwa ngazo. Nangona kunjalo, ngokubanzi, isigaba se-G1 sinokuhlala malunga ne-18 kwiiyure ze-30, isigaba se-S sithatha malunga ne-6 kwiiyure ze-8, isigaba se-G2 sinokuhlala malunga ne-2 ukuya kwiiyure ze-10, kwaye isigaba se-M (esibandakanya i-mitosis kunye ne-cytokinesis) sinokuhlala. phakathi kwemizuzu engama-30 ukuya kwiyure.
Umbuzo: Ziziphi izinto ezinokuchaphazela ixesha lesigaba ngasinye somjikelo weseli?
A: Ubude besigaba ngasinye somjikelezo weseli sinokuchaphazeleka kwizinto ezahlukeneyo. Ezinye zezi zinto ziquka uhlobo kunye nemeko yophuhliso lweseli, iimeko zokusingqongileyo, ubukho beempawu zokukhula kweeseli okanye umonakalo, kunye nefuthe lemfuza kunye ne-epigenetic.
Umbuzo: Kutheni kubalulekile ukwazi ixesha lesigaba ngasinye somjikelo weseli?
IMPENDULO: Ukwazi ixesha lesigaba ngasinye somjikelo weeseli kubalulekile ekuqondeni inkqubo yokwahlulwa kweeseli kunye nokulawulwa kokukhula kweeseli. Ukongeza, kubalulekile kuphononongo lwezifo ezinxulumene nokwanda kweeseli ezingalawulwayo, ezinjengomhlaza.
Umbuzo: Limiselwa njani ixesha lesigaba ngasinye somjikelo weseli?
A: Ixesha lesigaba ngasinye somjikelo weseli linokumiselwa kusetyenziswa iindlela zaselabhoratri ezibandakanya ukulandelela kunye nokuleyibhelishwa kweeseli kumanqanaba ahlukeneyo omjikelo. Obu buchule bunokusebenzisa iimpawu ze-fluorescent, i-microscopy, kunye nohlalutyo lomfanekiso ukuze ukhangele kwaye ulinganise iiseli kwisigaba ngasinye.
Umbuzo: Ngaba kukho ukungafani kwixesha lezigaba zomjikelezo weseli phakathi kwezinto eziphilayo ezahlukeneyo?
A: Ewe, kukho iyantlukwano kwixesha lezigaba zomjikelo weseli phakathi kwezinto eziphilayo ezahlukeneyo. Ngokomzekelo, kwizinto ezintsonkothileyo ezineeseli ezininzi, njengezilwanyana ezanyisayo, umjikelo weeseli udla ngokuba mde kunento ephilayo eneseli enye, njengeentsholongwane.
Umbuzo: Ngaba ubude bezigaba zomjikelezo weeseli zingatshintsha ekuphenduleni i-stimuli yangaphandle?
A: Ewe, ubude bezigaba zomjikelezo weseli bunokutshintsha ekuphenduleni i-stimuli yangaphandle. Ngokomzekelo, ubukho beempawu zokukhula kweeseli okanye umonakalo kunokukhawulezisa okanye ukulibazisa izigaba ezithile zomjikelo weseli.
Umbuzo: Ulwazi lwexesha lesigaba ngasinye somjikelo weseli lunokusetyenziswa njani kuphando lwezonyango kunye nekhemesti?
A: Ulwazi lwexesha lesigaba ngasinye somjikelezo weseli lunokusetyenziswa kuphando lwezonyango kunye ne-pharmacological ukuqonda kunye nokunyanga izifo ezinxulumene nokunyuka kweeseli ezingaqhelekanga. Ngaphaya koko, olu lwazi lunokunceda ekuyileni nasekuphuhliseni amachiza asebenza ngokuthe ngqo kwizigaba ezithile zomjikelo weseli.
Ukucamngca kokugqibela
Isishwankathelo, ukuqonda ixesha lesigaba ngasinye somjikelo weseli kubalulekile ukuqonda iinkqubo ezenzeka ngaphakathi kweeseli. Ukususela kwisigaba se-G1, apho iseli ikhula kwaye ilungiselela ukuphindaphinda izinto zayo zofuzo, ngokusebenzisa isigaba se-S, apho i-DNA synthesis yenzeke khona, de ifike kwisigaba se-G2 apho iseli ilungiselela ukwahlula, isigaba ngasinye sidinga ixesha laso lokuqinisekisa iseli efanelekileyo. ukuphindaphinda kunye nokwahlula.
Isigaba se-M, okanye isigaba se-mitosis, sibaluleke kakhulu, kuba ngeli nqanaba iseli iyahlukana ibe ziiseli zeentombi ezimbini kwaye igcine imathiriyeli yemfuzo ngokuchanekileyo. Isigaba ngasinye sinexesha laso kwaye silawulwa luluhlu lweendlela eziyinkimbinkimbi eziqinisekisa ukunyaniseka kunye nokuzinza komjikelo weseli.
Kuyimfuneko ukuba kuthathelwe ingqalelo ukuba kukho ukuhluka kwexesha lesigaba ngasinye kwiindidi ezahlukeneyo zeeseli nakwiimeko ezahlukeneyo zokusingqongileyo. Ngaphezu koko, naluphi na utshintsho kwixesha lezi zigaba lunokuba nemiphumo emibi, njengokubonakala kwezifo ezinxulumene nokunyuka kweeseli ezingalawulwayo, ezifana nomhlaza.
Isishwankathelo, ukuqonda ixesha lesigaba ngasinye somjikelezo weseli kubalulekile ukuqhubela phambili ukuqonda kwethu iinkqubo zeselula kunye nokulawulwa kwazo. Uphando olongezelelweyo kulo mmandla luya kuvumela ukuqonda ngcono izifo ezinxulumene nazo. kunye nomjikelo weseli kwaye kunokukhokelela kwiindlela ezintsha zonyango kwixesha elizayo.
NdinguSebastián Vidal, injineli yekhompyuter ethanda itekhnoloji kunye ne-DIY. Ngaphaya koko, ndingumdali we tecnobits.com, apho ndabelana ngee-tutorials ukwenza itekhnoloji ifikeleleke kwaye iqondeke kumntu wonke.