{"id":1359,"date":"2010-02-06T22:24:01","date_gmt":"2010-02-06T20:24:01","guid":{"rendered":"http:\/\/www.sorubak.com\/blog\/?p=1359"},"modified":"2010-02-06T22:24:01","modified_gmt":"2010-02-06T20:24:01","slug":"mayoz-bolunme-ve-evreleri","status":"publish","type":"post","link":"https:\/\/www.sorubak.com\/blog\/mayoz-bolunme-ve-evreleri.html","title":{"rendered":"Mayoz B\u00f6l\u00fcnme ve Evreleri"},"content":{"rendered":"
<\/strong>A)Mayoz-1 evreleri: <\/strong><\/p>\n
Mayoz b\u00f6l\u00fcnme homolog kromozomlar\u0131n ve karde\u015f kromatidlerin ayr\u0131lmas\u0131n\u0131 sa\u011flayan ard\u0131\u015f\u0131k iki b\u00f6l\u00fcnme b\u00fct\u00fcn\u00fcd\u00fcr. Homolog kromozomlar\u0131n ayr\u0131lmas\u0131na neden olan birinci evreye Mayoz-1 evreleri denir.
\na)Profaz-1 <\/strong>
\n1-Sentroiller kutuplara hareket eder.
\n2-Nucleus zar\u0131 ve e.r. zarlar\u0131 erimeye ba\u015flar.
\n3-\u0130\u011f iplikleri olu\u015fmaya ba\u015flar.
\n4-Kromozomlar k\u0131sal\u0131p kal\u0131nla\u015fmaya ba\u015flar. Ancak profaz-1\u2019 de Mitoz profaz\u0131nda ve profaz-2 \u2018de g\u00f6r\u00fclmeyen baz\u0131 \u00f6zg\u00fcn olaylar ve kromozomlar\u0131n \u00f6zel davran\u0131\u015flar\u0131 vard\u0131r. Bu nedenle profaz-1 kendi i\u00e7inde be\u015f alt evrede incelenir.<\/div>\n

I)Leptoten:<\/strong>
\n1-\u0130nce ve uzun iplikler halinde olan kromatinler k\u0131sal\u0131p kal\u0131nla\u015f\u0131rlar.
\n2-Nucleolus (\u00c7ekirdekcik) varl\u0131\u011f\u0131n\u0131 s\u00fcrd\u00fcr\u00fcr.
\nII)Zigoten:<\/strong>
\n1-Homolog kromozomlar yanyana gelerek \u00e7iftler (Bivalent yap\u0131) olu\u015ftururlar.
\n2-E\u015fle\u015fme b\u00fct\u00fcn kromozom \u00e7iftlerinde g\u00f6r\u00fcl\u00fcr.<\/p>\n

III)Pakiten<\/strong>:
\n1-Kromozomlar iyice k\u0131sal\u0131p kal\u0131nla\u015f\u0131r.
\n2-E\u015fle\u015fen homolog kromozomlar bu evrede birbirleri ilke iyice kayna\u015f\u0131rlar ve bu evrede h\u00fccrenin kromozom say\u0131s\u0131 n g\u00f6z\u00fck\u00fcr.
\n3-Evrenin sonunda her kromozom \u00e7iftinde d\u00f6rt kromatid g\u00f6r\u00fcl\u00fcr ve bu yap\u0131ya tetrad denir.H\u00fccrede g\u00f6r\u00fclen tetrad say\u0131s\u0131 n kadard\u0131r.
\n4-Bu evrede homolog kromozomlar\u0131n karde\u015f olmayan kromatidleri aras\u0131nda gen al\u0131\u015f veri\u015fi g\u00f6r\u00fcl\u00fcr bu olaya krossing-over denir.
\n5-Karde\u015f olmayan kromatidler aras\u0131ndaki \u00e7ak\u0131\u015fma noktalar\u0131na kiyazma denir.
\n6-Uzun kromozomlarda g\u00f6r\u00fclen kiyazma say\u0131lar\u0131 daha \u00e7oktur.<\/div>\n

IV)Diploten:<\/strong>
\n1-Tetrad olu\u015fturan kromozomlar birbirlerini iterek ayr\u0131lmaya ba\u015flarlar.
\n2-Ancak krossing-over b\u00f6lgelerinde kiyazmalarla ba\u011flant\u0131lar\u0131n\u0131 s\u00fcrd\u00fcr\u00fcrler.
\nV)Diakinez:<\/strong>
\n1-Kromozomlar daha fazla k\u0131sal\u0131rlar.
\n2-Homolog kromozomlarda ba\u011flant\u0131 sadece uca yak\u0131n yerlerde kal\u0131r.
\n3-\u00c7ekirdek zar kaybolur.
\n4-Nucleolus (\u00c7ekirdekcik) kaybolur.
\n5-\u0130\u011f iplikleri olu\u015fmu\u015ftur.
\n6-Di\u015filerde e\u015fey ana h\u00fccreleri ger\u00e7ekle\u015fen mayoz b\u00f6l\u00fcnmenin bu evresinde h\u00fccreler uzun s\u00fcre kal\u0131rlar. B\u00f6l\u00fcnmenin bundan sonraki evreleri ovulasyondan sonra devam eder.<\/p>\n<\/blockquote>\n

b)Metafaz-1<\/strong>
\n1-Homolog kromozomlar (Tetradlar halinde) ekvatoral plak \u00fczerinde kar\u015f\u0131l\u0131kl\u0131 dizilirler.
\n2-Her kromozom sentromeri ile i\u011f ipliklerine tutunurlar
\nc)Anafaz-1<\/strong>
\n1-Homolog kromozomlar i\u011f iplikleri ile z\u0131t kutuplara do\u011fru \u00e7ekilirler.
\n2-Karde\u015f kromatidleri bir arada tutan sentromerler par\u00e7alanmam\u0131\u015ft\u0131r.
\n3-Kiyazmalar kromozomlar\u0131n ucuna do\u011fru kayarak ortadan kalkar.
\n4-Anne ve babadan gelen kromozomlar\u0131n kutuplara ta\u015f\u0131nmas\u0131 rasgele olur buda \u00e7e\u015fitlilik nedenidir.<\/p>\n

d)Telofaz-1 <\/strong>
\n1-Kromozomlardaki helixler \u00e7\u00f6z\u00fcl\u00fcr.
\n2-Nucleus zar\u0131 belirginle\u015fir.
\n3-Sitokinezle iki h\u00fccre olu\u015fur.
\n4-Olu\u015fan h\u00fccrelerin kromozom yap\u0131s\u0131 n2c dir.
\n5-Erkeklerde sekonder spermatositler olu\u015fur.
\n6-Di\u015filerde ikincil oosit ve birinci kutup h\u00fccresi meydana gelir.
\n7-Mayoz ge\u00e7iren baz\u0131 h\u00fccrelerde nucleus zar\u0131 olu\u015fmaz ve kromozomlar helixler \u00e7\u00f6z\u00fclmez.
\nAra interfaz:Nucleolus g\u00f6r\u00fclmez,DNA ve RNA sentezi g\u00f6r\u00fclmez. H\u00fccredeki haz\u0131rl\u0131klar t\u0131pk\u0131 \u00f6nceki interfaz\u0131n devam\u0131 gibidir.
\nB)Mayoz-II evreleri<\/strong>
\nKarde\u015f kromatidlerin ayr\u0131lmas\u0131n\u0131 sa\u011flayan ikinci b\u00f6l\u00fcnme evrelerine Mayoz-2 evreleri denir. Mayoz interfaz\u0131nda g\u00f6r\u00fclen olaylar mitoz interfaz\u0131 ile ayn\u0131d\u0131r.
\na)Profaz-II<\/strong>
\n1-Birinci b\u00f6l\u00fcnmede olu\u015fan i\u011fipliklerine dik olarak i\u011f iplikleri olu\u015fur.
\n2-Olu\u015fmu\u015fsa nucleus zar\u0131 kaybolur.
\n3-Helixlerini \u00e7\u00f6zen kromozomlar tekrar helixlerini olu\u015fturur.
\nb)Metafaz-II<\/strong>
\n1-Kromozomlar ekvatoral d\u00fczlemde yanyana dizilirler
\n2-Kromatidler sentromerleri ile bir aradad\u0131r
\n3-Kromozomlar sentromerleri ile i\u011f ipliklerine tutunurlar
\nc)Anafaz-II<\/strong>
\n1-\u0130\u011f ipliklerinin itme ve \u00e7ekme hareketi ile sentromerler par\u00e7alan\u0131r.
\n2-Birbirinden ayr\u0131lan karde\u015f kromatidler z\u0131t kutuplara gider<\/p>\n

d)Telofaz-II <\/strong>
\n1-Kutuplara \u00e7ekilen kromatidler helixlerini \u00e7\u00f6zerek kromatin iplik haline ge\u00e7erler
\n2-Nucleus zar\u0131 olu\u015fur.
\n3-\u0130\u011f iplikleri kaybolur
\n4-Sitokinezle iki toplam d\u00f6rt h\u00fccre olu\u015fur.
\n5-Olu\u015fan h\u00fccrelerde ana h\u00fccrenin yar\u0131s\u0131 kadar kromozom dolay\u0131s\u0131yla DNA vard\u0131r
\n6-Olu\u015fan h\u00fccrelerdeki kal\u0131tsal materyal hem profaz-1 de ger\u00e7ekle\u015fen krossing-over hemde metafaz-1 deki homolog kromozomlar\u0131n diziliminin rasgele olmas\u0131ndan dolay\u0131 farkl\u0131d\u0131r
\n7-Olu\u015fan h\u00fccreler erkekte spermatid, di\u015filerde ise oosit denir<\/p>\n

Mayoz B\u00f6l\u00fcnmenin temel \u00f6zellikleri:<\/strong>
\n1-Sadece 2n kromozomlu h\u00fccrelerde g\u00f6r\u00fcl\u00fcr.
\n2-2n kromozomlu h\u00fccrelerden n kromozomlu 4 h\u00fccre olu\u015fur.
\n3-iki karyokinez ve iki sitokinez g\u00f6r\u00fcl\u00fcr.
\n4-E\u015fey ana h\u00fccresi ve spor ana h\u00fccrelerinde g\u00f6r\u00fcl\u00fcr.
\n5-B\u00f6l\u00fcnme sonunda gamet ve sporlar olu\u015fur.
\n6-Kal\u0131tsal \u00e7e\u015fitlilik nedenidir.Olu\u015fan h\u00fccreler kal\u0131tsal olarak birbirinden farkl\u0131d\u0131r.
\n7-E\u015feyli \u00fcremenin temel mekanizmas\u0131d\u0131r.
\n8-Mitoza g\u00f6re daha ileri bir \u00f6zelliktir
\n9-Hem homolog kromozomlarda hemde karde\u015f kromatidlerde ayr\u0131lma g\u00f6r\u00fcl\u00fcr.
\n10-Sinaps, tetrad ve krossing-over g\u00f6r\u00fcl\u00fcr.
\n11-Mayoz ge\u00e7irmi\u015f h\u00fccre tekrar mayoz ge\u00e7iremez ancak mitoz ge\u00e7irebilir.<\/p>\n

\n
Notlar… <\/strong>
\nMayozun evrimsel \u00f6nemi:<\/strong>
\n1-Krossing-overle kal\u0131tsal \u00e7e\u015fitlilik sa\u011flar
\n2-Kromozom say\u0131s\u0131n\u0131 yar\u0131ya indirerek, d\u00f6llenme sonunda t\u00fcre \u00f6zg\u00fc kromozom say\u0131s\u0131n\u0131n sabit kalmas\u0131n\u0131 sa\u011flar.<\/div>\n

Mayoz b\u00f6l\u00fcnme ile olu\u015fan yap\u0131lar:<\/strong>
\n1-Sperm 2-Ovum 3-Makrospor 4-Mikrospor 5-Spor
\nMayoz b\u00f6l\u00fcnmenin g\u00f6r\u00fcld\u00fc\u011f\u00fc h\u00fccreler:<\/strong>
\n1-Sperm ana h\u00fccresi (Hayvanlarda)
\n2-Ovum ana h\u00fccresi (Hayvanlarda)
\n3-Spor ana h\u00fccresi (\u00c7i\u00e7eksiz bitkilerde)
\n4-Makrospor ana h\u00fccresi (\u00c7i\u00e7ekli bitkilerde)
\n5-Mikrospor ana h\u00fccresi (\u00c7i\u00e7ekli bitkilerde)
\n6-Zigot (Su yosunlar\u0131nda)
\nMayoz b\u00f6l\u00fcnmenin g\u00f6r\u00fcld\u00fc\u011f\u00fc yap\u0131 ve organlar:<\/strong>
\n1-Testis 2-Ovaryum 3-sporangium 4-Anterler 5-Tohum tasla\u011f\u0131 (Ovaryum)\n<\/p><\/blockquote>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

A)Mayoz-1 evreleri: Mayoz b\u00f6l\u00fcnme homolog kromozomlar\u0131n ve karde\u015f kromatidlerin ayr\u0131lmas\u0131n\u0131 sa\u011flayan ard\u0131\u015f\u0131k iki b\u00f6l\u00fcnme b\u00fct\u00fcn\u00fcd\u00fcr. Homolog kromozomlar\u0131n ayr\u0131lmas\u0131na neden olan birinci evreye Mayoz-1 evreleri denir. a)Profaz-1 1-Sentroiller kutuplara hareket eder. 2-Nucleus zar\u0131 ve e.r. zarlar\u0131 erimeye ba\u015flar. 3-\u0130\u011f iplikleri olu\u015fmaya ba\u015flar. 4-Kromozomlar k\u0131sal\u0131p kal\u0131nla\u015fmaya ba\u015flar. Ancak profaz-1\u2019 de Mitoz profaz\u0131nda ve profaz-2 \u2018de g\u00f6r\u00fclmeyen baz\u0131 … Devam\u0131n\u0131 oku…<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[44,7],"tags":[],"_links":{"self":[{"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/posts\/1359"}],"collection":[{"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/comments?post=1359"}],"version-history":[{"count":0,"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/posts\/1359\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/media?parent=1359"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/categories?post=1359"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sorubak.com\/blog\/wp-json\/wp\/v2\/tags?post=1359"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}