YaDRO

YaDRO, hasta, dar biologiya qismi hayotan muhimmi hunayrii nabotot va hayvonotro guyand. Vobasta ba mavjud budan yo na budani Ya. dar hujayra hamai organizmho ba zukariotho va prokariotho taqsim meshavand. Ahamiyati Ya. misli sitoplazma baroi hujayra kalon ast. Dar Ya. molekulahoe hosil meshavand, ki akhbori genetikiro dar sitoplazma ba markazi sintezi safeda meorand. Ya.-ro bori nakhust s. 1825 olimi chekh Ya. Purkyane dar tukhmhujayrai murg mushohida kardaast. Ya.-i hujayrai rastaniro olimi anglis R. Broun (1831—33) va Ya.-i hujayrai hayvonro olimi nemis T. Shvann (1838—30) tavsif namudand.

Hujayra odatan yak Ya. dorad, ki kuramonand, mudavvar yo barjasta ast. Shakli Ya. bazan murakkab (lalmonand, shokharonda va g.; mas., Ya.-i leykositho) niz meshavad.- Baze hujayraho du yo yakchand Ya. dorand. Chunin hujayraho dar natijai taqsim nashudani sitoplazma va taqsim shudani Ya. yo omekhta gashtani yakchand hujayrai yak yadroi ba vujud meoyand. Andozai Ya. az 1 mkm (dar baze soddatarinho) to ~ 1 mm (baze hujayratukhmho) ast. Ya. az sitoplazma bo jildi yadro (az du qabat parda iborat ast) judo meshavad. Pardai berun in jildi Ya. odatan shomili ribosomaho buda, jo-jo ba shabakai endoplazmavi yak megardad. Tavassuti masomahoi jildi Ya. bayni Ya. va sitoplazma mubodilai modda ba amal meoyad. Tarkibi khimiyavii Ya. murakkab ast. Dar tarkibi Ya. shirai yadro (karpolimfa, karioplazma), khromatin, khromosomaho, yadrocha va g. mavjudand. Hayoti hujayra az du davrai asosi — interfaza (yo davrai mubodilai moddaho) va mitoz (yo davrai taqsimshavi) iborat ast. Ya. dar davrai nnterfaza orom buda, dar sintezi safeda, khromatin (kompleksi KDN bo safeda) tanzimi shaklpaydoshavi va g. ishtirok mekunad. Dar davrai taqsimshavi boshad, dar Ya. tagyirote ruy medihad, ki on boisi aznavtaqsimshavii khromosoma va bavujudoii D.-i dukhtari megardad. Ya. faqat bo rohi taqsimshavi meafzoyad, ki dar natija khudi hujayra niz taqsim meshavad. Odatan du navi taqsimshavii Ya. (amitoz va mitoz) hast. Baze Ya.-ho ba yakchand qism taqsim meshavand.