Home / Ilm / KISLOTAI DEZOKSIRIBONUKLEAT (KDN)

KISLOTAI DEZOKSIRIBONUKLEAT (KDN)

kislota-dezoksirKISLOTAI DEZOKSIRIBONUKLEAT (KDN), navi kislotahoi nukleat, ki dar tabiati zinda pahn shudaast. KDN az asoshoi purini (adenin, guanin) va piramidini (timin, sitozin, 5-metilsitozin), qandi dezoksiriboza va boqimondai kislotai fosfat tarkib yoftaast. Asosan dar yadroi hujayra dar shakli dezoksiribonukleoproteidho (DNP) mavjud ast. KDN vazifai nigahdori va guzaronidani akhbori genetikii doir ba sokht va alomathoi organizmhoi zindaro ijro mekunad. Doruhoi KDN-ro az boftai hayvonot va rastani, inchunin az bakteriyaho va virushoi KDN-dor hosil kardan mumkin ast. ADN biopolimerest, ki az monomerhoi ziyodi dezoksiribonukleotidho tarkib yoftaast; vazni molekulaviash 106 – 109. Muvofiqi modeli sokhtorii s. 1953 peshnihod namudai J. Uotson va F. Krik KDN az du zanjiri polinukleotidii dar spirali duqabatai tobkhurda va bo bandhoi gidrogenii bayni asoshoi nitrogeni ba ham payvastshuda (adenin – A bo timin – T, guanin – G bo sitozin – S yo 5-metilsitozin) iborat ast.
CHunin sokhtori khos na tanho khususiyathoi biologii KDN, balki khususiyathoi fizikiyu khimiyavii on (khosiyati kislotagi, boshiddat furubarii nurhoi ultrabunafsh, gudozishi mahlulhoi KDN dar 80 – 90°S va g.)-ro niz darbar megirad. Har yak organizmi zinda bo KDN-i ba khud khos, ki tanosubi muayyani nukleotid dorand va bo tartibi muayyan joygir shudaand, tavsif meshavand. Akhbori genetiki doir ba hamai alomathoi har yak organizm dar namudi pay dar payi muayyani nukleotidho dar KDN ramz karda va nigoh doshta meshavad. KDN yagona moddaest, ki qobiliyati khudduchandshavi (replikatsiya) dorad. Hangomi replikatsiya spirali duqabatai KDN kushoda shuda, dar har yak zanjiri polinukleotidi, chun dar matritsa, bo ishtiroki fermenti polimeraza zanjiri navi nukleotidi sintez meshavad. Har yak spirali ba tozagi hosilshudai KDN nuskhai sahehi KDN-i «modari» meboshad. In ravand asosi az nasl ba nasl guzarondani akhbori genetikiro tashkil medihad. KDN inchunin baroi sintezi kislotahoi ribonukleat (KRN) chun matritsa khizmat mekunad.
Dar tadqiqi ahamiyati biologii KDN olimoni Tojikiston niz sahmi khudro guzoshtaand. Dar In-ti botanika, fiziologiya va biofizikai rastanihoi AI JT miqdori 5-metilsitozin dar KDN-i rastanihoi gunogun va ahamiyati on dar tagyiryobii sokhti molekulai KDN muayyan karda shudaast. Dar barobari in, usuli makhsusi judo kardani KDN az khromosomaho va omuzishi sokhti onho daryoft shudaast. Olimoni DDTT ba nomi Abuali ibni Sino tasiri gormonhoro ba qobiliyati sintezi KDN dar boftahoro muqarrar kardaand (baroi muolijai baze bemoriho istifoda meshavad).

Загрузка...

Dar boramon

Инчунин кобед

planet

ZAMIN – SAYYORAI SISTEMAM OFTOBI

Sababhoi tagyiryobii faslhoi sol. Az kursi tabiatshinosi mo medonem, ki Oftob in markazi sistemai oftobii mo …