1-) DNA NED\u0130R VE NEREDE BULUNUR ?<\/p>\n
DNA “Deoksi Ribo N\u00fckleik Asit” isimli bir t\u00fcr molek\u00fcl grubunun k\u0131salt\u0131lm\u0131\u015f isimidir. DNA’n\u0131n \u00e7ift zincirli ip merdivene benzer. \u00c7ift zincirli yap\u0131daki DNA zinciri olduk\u00e7a uzun bir zincirdir.Bu zincir h\u00fccre i\u00e7indeki \u00f6zel enzimler ve proteinler arac\u0131l\u0131\u011f\u0131 ile paketlenir. Nas\u0131l ki uzun bir ipi makaraya d\u00fczenli bir \u015fekilde sar\u0131yorsan\u0131z, h\u00fccrede buna benzer bir mekanizma ile DNA y\u0131 paketleyerek \u00e7ekirde\u011finin (Nukleus) i\u00e7ine yerle\u015ftirir.DNA her h\u00fccrede bulunur.\u00d6rne\u011fin b\u00f6breklerinizin h\u00fccrelerinde, karaci\u011ferinizin h\u00fccrelerinde, kemik h\u00fccrelerinizde k\u0131sacas\u0131 v\u00fccudunuzdaki her h\u00fccrede DNA molek\u00fcl\u00fc mevcuttur. <\/p>\n
2-) DNA\u2019NIN KE\u015eF\u0130: M\u0130ESCHER : 1869 y\u0131llar\u0131nda ilk olarak Miescher taraf\u0131ndan h\u00fccre \u00e7ekirde\u011finde \u00f6zel bir madde bulundu ve buna Miescher \u201c N\u00fcklein\u201d ad\u0131n\u0131 verdi . Daha sonra ise n\u00fckleit asitlerin iki tipte oldu\u011fu anla\u015f\u0131ld\u0131 . Birincisi tim\u00fcsten elde edilen timon\u00fckleik asit, ikincisi bira mayalar\u0131ndan elde edilen zimon\u00fckleik asit . Timon\u00fckleik asit hayvanlar alemine , zimon\u00fckleik asit ise bitkiler alemine \u00f6zg\u00fc say\u0131ld\u0131. <\/p>\n
FEULGEN \u2013 ROSSENBECK : 1924 y\u0131llar\u0131nda ise Feulgen ve Rossenbeck timon\u00fckleik asidin \u00e7ok duyarl\u0131 bir tepkimesini tan\u0131mlad\u0131lar ; b\u00f6ylece her iki n\u00fckleik asidin her iki canl\u0131lar aleminde bulundu\u011fu ispat edilebildi. ondan sonra timon\u00fckleik asit \u00e7ekirde\u011fe , zimon\u00fckleik asit ise sitoplazmaya ait \u00f6zg\u00fc yap\u0131 maddeleri say\u0131ld\u0131. <\/p>\n
LEVENE \u2013 MOR\u0130 : 1929 y\u0131l\u0131nda Levene ve Mori taraf\u0131ndan timon\u00fckleik asidin DNA , zimon\u00fckleik asidin ise RNA Oldu\u011fu anla\u015f\u0131ld\u0131. <\/p>\n
WATSON \u2013 CR\u0130CK : 1953 y\u0131l\u0131nda Watson ve Crick DNA molek\u00fcl\u00fcn\u00fcn kendine has \u00f6zelliklere sahip bir \u00e7ift sarmal yap\u0131 halinde bulundu\u011funu ileri s\u00fcrd\u00fcler. Bu ara\u015ft\u0131r\u0131c\u0131lar\u0131n \u00f6nerdikleri DNA yap\u0131s\u0131 o tarihlerde ba\u015fka ara\u015ft\u0131r\u0131c\u0131lar taraf\u0131ndan ortaya konulan DNA ya ili\u015fkin \u00f6nemli bulgulara dayanmaktad\u0131r. Bunlardan biri, Wilkins ve Franklin taraf\u0131ndan, izole edilmi\u015f DNA fibrillerinin X-ray \u0131\u015f\u0131nlar\u0131n\u0131 k\u0131rma \u00f6zelliklerinin a\u00e7\u0131klanmas\u0131d\u0131r. Elde edilen X \u0131\u015f\u0131n\u0131 foto\u011fraflar\u0131, DNA n\u0131n zincirlerindeki bazlar\u0131n dizili\u015f s\u0131ras\u0131na ba\u011fl\u0131 olmaks\u0131z\u0131n, \u00e7ok d\u00fczenli bi\u00e7imde d\u00f6n\u00fcmler yapan bir molek\u00fcl oldu\u011funu g\u00f6stermektedir. Ayr\u0131ca TMV (t\u00fct\u00fcn Mozaik Vir\u00fcs\u00fc) \u00fczerinde yap\u0131lan \u00e7al\u0131\u015fmalar da DNA ile ilgili \u00e7al\u0131\u015fmalarda \u0131\u015f\u0131k tutmu\u015ftur.
\n \u0130\u015fte Watson ve Crick bu bulgular\u0131 de\u011ferlendirerek b\u00f6yle \u00f6zelliklere sahip DNA makro molek\u00fcl\u00fcn\u00fcn sekonder yap\u0131s\u0131na ait bir model geli\u015ftirdiler. Bu modele g\u00f6re, bir \u00e7ok sorunun a\u00e7\u0131klanmas\u0131 yap\u0131labildi\u011finden dolay\u0131 1962 y\u0131l\u0131nda bu iki bilim adam\u0131na NOBEL \u00d6D\u00dcL\u00dc verildi.<\/p>\n
Bir ba\u015fka \u00f6nemli bulguda Chargaff taraf\u0131ndan saptanm\u0131\u015ft\u0131r. Herhangi bir t\u00fcre ait DNA n\u0131n n\u00fckleotidlerine par\u00e7aland\u0131\u011f\u0131nda serbest kalan nukleotidlerde adenin miktar\u0131n\u0131n timine, guanin miktar\u0131n\u0131n da sitozine daima e\u015fit oldu\u011funun saptanmas\u0131d\u0131r.. Yani Chargaff kural\u0131\u2018na g\u00f6re do\u011fal DNA molek\u00fcllerinde adeninin timine veya guaninin sitozine oran\u0131 daima 1\u2019e e\u015fittir. (A\/T=1 ve G\/C=1).<\/p>\n
3-) DNA\u2019NIN \u015eEKL\u0130 VE YAPISI :
\n DNA molek\u00fcl\u00fc, heliks (=sarmal) \u015feklinde k\u0131vr\u0131lm\u0131\u015f, iki kollu merdiven \u015feklindedir. Kollar\u0131n\u0131, yani merdivenin kenarlar\u0131n\u0131, \u015feker (deoksiriboz) ve fosfat molek\u00fclleri meydana getirir. Deoksiriboz ile fosfat gruplar\u0131 ester ba\u011flar\u0131yla birbirlerine ba\u011flanm\u0131\u015ft\u0131r. \u0130ki kolun aras\u0131ndaki merdiven basamaklar\u0131nda geli\u015fig\u00fczel bir s\u0131ralanma yoktur; her zaman Guanin (G), Sitozin\u2019in (C ya da S); Adenin (A), Timin\u2019in (T) kar\u015f\u0131s\u0131na gelir. Hem p\u00fcrin (yani adenin ve guanin) ile pirimidin (yani sitozin ile timin) aras\u0131ndaki hidrojen ba\u011flar\u0131, hemde di\u011fer ba\u011flar, meydana gelen heliksin d\u00fczg\u00fcn olmas\u0131n\u0131 sa\u011flar. P\u00fcrin ve pirimidin bazlar\u0131, yandaki \u015fekerlere (Riboz), glikozidik ba\u011flarla ba\u011flanm\u0131\u015ft\u0131r. Baz, \u015feker ve fosfat kombinasyonu, \u00e7ekirdek asitlerinin temel birimleri olan n\u00fckleotidleri meydana getirmi\u015ftir. D\u00f6rt \u00e7e\u015fit n\u00fckleotid vard\u0131r. Bunlar ta\u015f\u0131d\u0131klar\u0131 bazlara g\u00f6re isimlendirilirler (Adenin, Guanin, Sitozin,Timin).
\n N\u00dcKLEOZ\u0130T
\n AZOTLU ORGAN\u0130K BAZ + DEOKS\u0130R\u0130BOZ \u015eEKER\u0130 + FOSFOR\u0130K AS\u0130T
\n N\u00dcKLEOT\u0130T<\/p>\n
N\u00fckleotidler birbirlerine fosfat ba\u011flar\u0131yla ba\u011flanarak, \u015feker ve fosfat k\u0131s\u0131mlar\u0131n\u0131n birbirlerini izledi\u011fi serilerden olu\u015fan bir omurgaya sahip uzun ve dallanm\u0131\u015f polin\u00fckleotid zincirlerini meydana getirmi\u015ftir. Kovalent ester ba\u011flar\u0131 veya fosfodiester ba\u011flar\u0131 olarak da bilinen bu ba\u011flar son derece kuvvetlidir.<\/p>\n
Fosfodiester ba\u011flar\u0131n\u0131n varl\u0131\u011f\u0131 DNA molek\u00fcl\u00fcn\u00fcn tek zincirli yap\u0131 halinde iken bile dayan\u0131kl\u0131 ve stabil yap\u0131da olmas\u0131n\u0131 sa\u011flar. Genetik m\u00fchendisli\u011finin hedeflerinden biri olan klonlama \u00e7al\u0131\u015fmalar\u0131, do\u011fal yolla ger\u00e7ekle\u015fmesi m\u00fcmk\u00fcn olmayan kovalent ba\u011f k\u0131r\u0131lmalar\u0131n\u0131 ger\u00e7ekle\u015ftirerek yeni t\u00fcrler olu\u015fturma \u00e7abalar\u0131n\u0131 arar.
\n Hidrojen ba\u011flar\u0131 daima bir p\u00fcrin(A,G) ile bir pirimidin (T,C) baz\u0131 aras\u0131ndan meydana gelir. A-T baz \u00e7iftinde 2 hidrojen ba\u011f\u0131, G-C baz \u00e7iftleri aras\u0131nda ise 3 hidrojen ba\u011f\u0131 bulunmaktad\u0131r. Hidrojen ba\u011flar\u0131n\u0131n \u00f6zelle\u015fmesi; anahtar kilit modelinini and\u0131ran, uygun nukleotid molek\u00fcllerinin kar\u015f\u0131l\u0131kl\u0131 gelerek birbirlerine yine uygun say\u0131da hidrojen ba\u011flar\u0131 ile ba\u011flanmas\u0131n\u0131 sa\u011flar. B\u00f6ylece zincirin bir kolunda bulunan nukleotidlerin dizili\u015fi,kar\u015f\u0131 kolda bulunan nukleotidlerin dizili\u015fini bir \u00e7e\u015fit dikte ve kontrol eder. Tesad\u00fcfe b\u0131rakmayan bir titizlikle molek\u00fcl yap\u0131s\u0131 olu\u015fturulur ve kontrol edilir.
\n DNA molek\u00fcl\u00fcn\u00fcn en \u00f6nemli \u00f6zellik iki polin\u00fckleotid zincirin birbirinin tamamlay\u0131c\u0131s\u0131 olmas\u0131d\u0131r. Pozitif (+) ve negatif (\u2013) iki polinukleotid zincirlerinin tamamlay\u0131c\u0131l\u0131k \u00f6zelli\u011fi,genetik materyalin i\u015flevlerini do\u011fru bi\u00e7imde nas\u0131l yapabildi\u011finin a\u00e7\u0131klanmas\u0131 a\u00e7\u0131s\u0131ndan DNA\u2019n\u0131n en \u00f6nemli temel \u00f6zelliklerinin ba\u015f\u0131nda gelir.
\n DNA bir organizman\u0131n olu\u015fuma ili\u015fkin bilgileri ta\u015f\u0131r.DNA molek\u00fclleri, h\u00fccre \u00e7ekirde\u011finde bulunurlar ve v\u00fccudumuzda bulunan t\u00fcm proteinleri olu\u015fumu s\u0131ras\u0131ndaki kodlam\u0131\u015f bilgileri i\u00e7erir.DNA\u2019n\u0131n protein yapma i\u015flemi ,inan\u0131lmayacak derecede kusursuzdur.<\/p>\n","protected":false},"excerpt":{"rendered":"
1-) DNA NED\u0130R VE NEREDE BULUNUR ? DNA “Deoksi Ribo N\u00fckleik Asit” isimli bir t\u00fcr molek\u00fcl grubunun k\u0131salt\u0131lm\u0131\u015f isimidir. DNA’n\u0131n \u00e7ift zincirli ip merdivene benzer. \u00c7ift zincirli yap\u0131daki DNA zinciri olduk\u00e7a uzun bir zincirdir.Bu zincir h\u00fccre i\u00e7indeki \u00f6zel enzimler ve proteinler arac\u0131l\u0131\u011f\u0131 ile paketlenir. Nas\u0131l ki uzun bir ipi makaraya d\u00fczenli bir \u015fekilde sar\u0131yorsan\u0131z, h\u00fccrede …<\/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":[5966,8885,6323,8887,8888,5673,2284,2303,8886,6327],"class_list":["post-3904","post","type-post","status-publish","format-standard","hentry","category-fen-ve-teknoloji-odevleri","category-odevler","tag-deoksi-ribo-nukleik-asit","tag-dna-ile-ilgili-bilgiler","tag-dna-molekulu","tag-fosfodiester-baglar","tag-hidrojen-baglari","tag-nukleotidler","tag-nukleus","tag-protein","tag-timonukleik-asit","tag-watson-ve-crick"],"_links":{"self":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/3904","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=3904"}],"version-history":[{"count":0,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/posts\/3904\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/media?parent=3904"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/categories?post=3904"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.islamidavet.com\/kutuphane\/wp-json\/wp\/v2\/tags?post=3904"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}