H\u00dcCRE B\u00d6L\u00dcNMELER\u0130<\/p>\n
H\u00fccreler ya canl\u0131lar\u0131n b\u00fcy\u00fcy\u00fcp geli\u015fmesi, rejenerasyonu ve dokular\u0131n\u0131n yenilenmesi ya da \u00fcreme faaliyetlerinin ger\u00e7ekle\u015ftirilmesi amac\u0131yla b\u00f6l\u00fcn\u00fcr. B\u00f6l\u00fcnmelere detaylar\u0131yla ge\u00e7meden \u00f6nce h\u00fccrelerin ni\u00e7in b\u00f6l\u00fcnd\u00fckleri konusundaki g\u00f6r\u00fc\u015flere yer verelim. H\u00fccre, b\u00fcy\u00fckl\u00fck bak\u0131m\u0131ndan belirli bir s\u0131n\u0131ra ula\u015ft\u0131\u011f\u0131 zaman, kuramsal olarak ikiye b\u00f6l\u00fcnmesi gereklidir. \u00c7\u00fcnk\u00fc h\u00fccre genel olarak bir k\u00fcre \u015feklinde d\u00fc\u015f\u00fcn\u00fcl\u00fcrse, b\u00fcy\u00fcmede hacim y\u00fczey orant\u0131s\u0131 r3 \/ r2 ‘dir. Yani hacim yar\u0131\u00e7ap\u0131n k\u00fcp\u00fcyle artarken, y\u00fczeydeki b\u00fcy\u00fcme yar\u0131\u00e7ap\u0131n karesine ba\u011f\u0131ml\u0131 kal\u0131r ve bir s\u00fcre sonra h\u00fccrenin y\u00fczeyi gerek besin al\u0131\u015f veri\u015fini gerek art\u0131k maddelerin at\u0131l\u0131m\u0131n\u0131 ve gerekse gaz al\u0131\u015f veri\u015fini b\u00fct\u00fcn h\u00fccreye sa\u011flayamayacak duruma gelir ve h\u00fccre, y\u00fczeyini art\u0131rmak amac\u0131yla b\u00f6l\u00fcnmeye ba\u015flar. Ayr\u0131ca b\u00fcy\u00fcyen h\u00fccrede sitoplazma \u00e7ekirdek oran\u0131 artt\u0131\u011f\u0131ndan ve \u00e7ekirde\u011fin etki alan\u0131 s\u0131n\u0131rl\u0131 oldu\u011fundan bu durum h\u00fccreyi \u00f6l\u00fcme s\u00fcr\u00fckleyebilir, dolay\u0131s\u0131yla h\u00fccreyi b\u00f6l\u00fcnmeye zorlar. (Bu fikri 1908 y\u0131l\u0131nda ilk defa HERTWIG ortaya atm\u0131\u015ft\u0131r.) h\u00fccrenin i\u00e7ine yapay olarak iki \u00e7ekirdek yerle\u015ftirildi\u011finde ya da \u00e7ekirdek i\u00e7indeki kromozom say\u0131s\u0131 iki kat\u0131na \u00e7\u0131kar\u0131ld\u0131\u011f\u0131nda, h\u00fccrenin hacmi normal b\u00fcy\u00fckl\u00fc\u011f\u00fcn\u00fcn iki misli olabilir. Bu, \u00e7ekirde\u011fin s\u0131n\u0131rl\u0131 bir etkiye sahip oldu\u011funu kan\u0131tlar. Uygun x-\u0131\u015f\u0131n\u0131na tutulan h\u00fccrelerde kal\u0131tsal materyal \u00e7o\u011falmas\u0131 olur; fakat b\u00f6l\u00fcnme meydana gelmez ve sonu\u00e7ta h\u00fccre b\u00fcy\u00fcmesiyle birlikte h\u0131zl\u0131 h\u00fccre \u00e7o\u011falmas\u0131 da g\u00f6r\u00fcl\u00fcr (kanserle\u015fmede oldu\u011fu gibi). B\u00f6l\u00fcnecek b\u00fcy\u00fckl\u00fc\u011fe ula\u015fan amipin (normal olarak iki g\u00fcnde bir b\u00f6l\u00fcn\u00fcr) protoplazmas\u0131ndan bir miktar kesersek (100 g\u00fcn s\u00fcreyle) b\u00f6l\u00fcnme durur ve tekrar b\u00fcy\u00fcmeye ba\u015flar. Bu uygulama sonsuz olarak s\u00fcrd\u00fcr\u00fcl\u00fcrse, amip, b\u00f6l\u00fcnmeden hayatta kalabilir. <\/p>\n
B\u00f6l\u00fcnmeye ba\u015flayan ba\u011f doku h\u00fccrelerinin \u00e7ap\u0131 yakla\u015f\u0131k % 12 kadar artar. Buna kar\u015f\u0131n b\u00fcy\u00fckl\u00fc\u011f\u00fc s\u0131n\u0131rland\u0131r\u0131lm\u0131\u015f h\u00fccrelerde b\u00fcy\u00fcme durur. <\/p>\n
Bir h\u00fccreli canl\u0131larda mitoz ayn\u0131 zamanda \u00fcremeyi sa\u011flar. Her canl\u0131da ve ayn\u0131 bireyin farkl\u0131 dokular\u0131ndaki h\u00fccrelerin mitozla b\u00f6l\u00fcnme h\u0131z\u0131 tamamen farkl\u0131d\u0131r. \u00d6rme\u011fin ba\u011f\u0131rsak mukozas\u0131ndaki, epidermisteki, kan h\u00fccrelerini \u00fcreten dokulardaki h\u00fccrelerin s\u00fcrekli b\u00f6l\u00fcnmesine kar\u015f\u0131l\u0131k, di\u011fer dokular\u0131n h\u00fccreleri belirli zamanlarda, sinir ve retina h\u00fccreleri ise 20-25 ya\u015f\u0131n \u00fcst\u00fcnde (insanda \u00e7o\u011funluk ana karn\u0131nda 4. aydan itibaren sonra) hi\u00e7 b\u00f6l\u00fcnmez.<\/p>\n
Mitoz b\u00f6l\u00fcnmenin amac\u0131 ana h\u00fccredeki kal\u0131t\u0131m materyalinin e\u015fit \u015fekilde yavru h\u00fccrelere verilmesidir. Bir h\u00fccrelilerdeki amitoz b\u00f6l\u00fcnmede, hem i\u011f iplikleri i\u015fe kar\u0131\u015fmaz hem de kal\u0131t\u0131m materyali yavrulara b\u00fcy\u00fck bir olas\u0131l\u0131kla e\u015fit verilmez. Mitoz b\u00f6l\u00fcnme s\u00fcrekli bir olay olmas\u0131na kar\u015f\u0131l\u0131k, izlemede ve anlamada kolayl\u0131k olsun diye evrelere ayr\u0131larak incelenir. Dinlenme s\u0131ras\u0131nda, kromozomlar boyanmaz. DNA miktar\u0131 2n’dir (G1-Evresi). Daha sonra DNA kendini e\u015fler. DNA miktar\u0131 4n’dir. \u0130nce kromatid iplikler \u015feklinde boyan\u0131rlar (S-Evresi). \u00dc\u00e7\u00fcnc\u00fc evre koyu boyanan kromozomlara sahip, 4n’li evredir (G2-Evresi). Son evre ise mitoz b\u00f6l\u00fcnmeni ger\u00e7ekle\u015fti\u011fi ve kromozom say\u0131s\u0131n\u0131n 2n’e indi\u011fi evredir (M-Evresi). H\u00fccredeki t\u00fcm yap\u0131lar\u0131n birle\u015ferek, daha sonra iki yavru h\u00fccreye verilmesini sa\u011flayan bu d\u00f6ng\u00fcye h\u00fccre d\u00f6ng\u00fcs\u00fc denir. <\/p>\n
Bitki ve hayvanlarda h\u00fccre d\u00f6ng\u00fcs\u00fcn\u00fcn tamamlanmas\u0131 yakla\u015f\u0131k 20 saat kadar s\u00fcrer. Bu s\u00fcrenin yakla\u015f\u0131k bir saati mitoz b\u00f6l\u00fcnmeye ayr\u0131lm\u0131\u015ft\u0131r. Geri kalan s\u00fcre interfazdaki b\u00fcy\u00fcme i\u00e7in kullan\u0131l\u0131r. en uygun beslenme ve s\u0131cakl\u0131k ko\u015fullar\u0131nda dahi, herhangi bir h\u00fccre \u00e7e\u015fidinin b\u00f6l\u00fcnme s\u00fcresi sabittir. Uygun olmayan ko\u015fularda bu s\u00fcre uzayabilir. Fakat her h\u00fccrenin optimumdan daha h\u0131zl\u0131 b\u00fcy\u00fcmesini hem de optimumdan daha h\u0131zl\u0131 d\u00f6ng\u00fcs\u00fcn\u00fc sa\u011flamak olanaks\u0131zd\u0131r. bundan \u015fu sonuca varabiliriz; her h\u00fccrenin d\u00f6ng\u00fc s\u00fcresi kusursuz bir zamanlamayla geli\u015fecek \u015fekilde programlanm\u0131\u015ft\u0131r. Bu program iki a\u015famada y\u00fcr\u00fct\u00fcl\u00fcr. \u0130lkinde kromozomlardaki kal\u0131tsal materyal iki kat\u0131na \u00e7\u0131kar\u0131l\u0131r, ikincisinde ise h\u00fccrenin di\u011fer organelleri \u00e7o\u011falt\u0131l\u0131r.
\n D\u00f6llenmi\u015f yumurtalarda b\u00f6l\u00fcnme, al\u0131\u015f\u0131lm\u0131\u015f\u0131n tersine bir saatte ya da daha az bir s\u00fcre i\u00e7erisinde tamamlan\u0131r. \u00c7\u00fcnk\u00fc yumurta h\u00fccresine, yumurtan\u0131n olgunla\u015fmas\u0131 s\u0131ras\u0131nda her \u00e7e\u015fit molek\u00fclden bol miktarda verilmi\u015ftir. B\u00f6ylece yumurta h\u00fccresi h\u0131zla b\u00f6l\u00fcnerek gittik\u00e7e daha k\u00fc\u00e7\u00fck h\u00fccreleri yapar. Bunlardaki h\u00fccre d\u00f6ng\u00fcs\u00fcnde b\u00fcy\u00fcme evresi yoktur, yaln\u0131z b\u00f6l\u00fcnme i\u00e7in haz\u0131rl\u0131k yap\u0131l\u0131r. Bu nedenle yakla\u015f\u0131k bir saatte bir b\u00f6l\u00fcnebilir<\/p>\n","protected":false},"excerpt":{"rendered":"
H\u00dcCRE B\u00d6L\u00dcNMELER\u0130 H\u00fccreler ya canl\u0131lar\u0131n b\u00fcy\u00fcy\u00fcp geli\u015fmesi, rejenerasyonu ve dokular\u0131n\u0131n yenilenmesi ya da \u00fcreme faaliyetlerinin ger\u00e7ekle\u015ftirilmesi amac\u0131yla b\u00f6l\u00fcn\u00fcr. B\u00f6l\u00fcnmelere detaylar\u0131yla ge\u00e7meden \u00f6nce h\u00fccrelerin ni\u00e7in b\u00f6l\u00fcnd\u00fckleri konusundaki g\u00f6r\u00fc\u015flere yer verelim. H\u00fccre, b\u00fcy\u00fckl\u00fck bak\u0131m\u0131ndan belirli bir s\u0131n\u0131ra ula\u015ft\u0131\u011f\u0131 zaman, kuramsal olarak ikiye b\u00f6l\u00fcnmesi gereklidir. \u00c7\u00fcnk\u00fc h\u00fccre genel olarak bir k\u00fcre \u015feklinde d\u00fc\u015f\u00fcn\u00fcl\u00fcrse, b\u00fcy\u00fcmede hacim y\u00fczey orant\u0131s\u0131 r3 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1407,1403],"tags":[2591,5779,5782,5781,2568,5780,5670],"class_list":["post-2297","post","type-post","status-publish","format-standard","hentry","category-fen-ve-teknoloji-odevleri","category-odevler","tag-bag-doku","tag-hucre-bolunmeleri","tag-hucre-dongusu","tag-kromozomlar","tag-mitoz","tag-mitoz-bolunmenin-amaci","tag-rejenerasyon"],"_links":{"self":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/2297","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/comments?post=2297"}],"version-history":[{"count":0,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/2297\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/media?parent=2297"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/categories?post=2297"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/tags?post=2297"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}