Deoxyribonucleic acid. Model Crick da kuma Watson

A farko bayani game da sinadaran Properties na deoxyribonucleic acid ake kwanan rana 1868 shekara. A cikin karni na 20th zuwa farkon na forties, an tabbatar da cewa kwayoyin ne mikakke polymer. Kamar yadda monomer raka'a yi nucleotides cewa kunshi wani nitrogenous tushe, mai pentose da kuma phosphate kungiyar (a biyar-carbon sugar).

Deoxyribonucleic acid na iya samun wani tushe na iri biyu: a pyrimidine (taimain (T) da kuma saitosin (C)) da kuma wani purine (adenine (A) da kuma Bibyun (G)). A fili ne da za'ayi amfani da nucleotide phosphodiester bond.

Masana kimiyyar halitta Watson da Crick a 1953 shekara, shan a matsayin dalilin X-ray bincike na DNA lu'ulu'u ƙarasa da cewa 'yan qasar kwayoyin kunshi wata biyu daga cikin polymer sarƙoƙi, kafa biyu Helix. Polynucleotide sarkar rauni a kan juna, ana gudanar tare da nufin na hydrogen shaidu cewa, samar tsakanin karin (yardatayya daidai) da kwasfansu a gaban sarƙoƙi. Lokacin da wannan biyu kafa kawai kamar haka: adenine-taimain, Bibyun-saitosin. Karfafawa ne da za'ayi ta biyu farko da na biyu da nau'i-nau'i - uku hydrogen shaidu.

The biyu-stranded deoxyribonucleic acid yana da tsawon lasafta a matsayin yawan nau'i-nau'i daga yardatayya daidai nucleotides (BP). Ga waɗanda kwayoyin, wanda ya kunshi miliyoyin da kuma dubban ma'aurata m.n.p. raka'a dauka kuma kb, bi da bi. Saboda haka, deoxyribonucleic acid mutum chromosome aka wakilta daya biyu Helix. Its tsawon shi ne 263 Mb a

DNA denaturation (narkewa) ne tsarin inda a yau da kullum biyu Helix mikakke kwayoyin wuce a cikin nada jihar. Bayan narkewa, biyu-kwayoyin ne zuwa kashi daban kewaye. A zafin jiki a wadda rabin Deoxyribonucleic acid narke, a narkewa batu. Ya dogara da ingancin daga cikin kwayoyin abun da ke ciki.

Kamar yadda riga aka ambata a sama, da G-C nau'i-nau'i ake stabilized da uku, da kuma biyu daga A-T - biyu hydrogen shaidu. Haka kuma, mafi girma da rabo daga farko nau'i-nau'i, mafi barga zai zama kwayoyin. Lokacin da denaturation na wani zango na 260 nm qara sha na haske. Wannan hyperchromic sakamako sa ya yiwu don samar da iko a kan kwayoyin jihar na sakandare tsarin. Idan bayani ne a sannu a hankali sanyaya zubi acid tsakanin karin strands na rauni links za a iya kafa a sake, na iya zama wani karkace tsari ne m ga 'yan qasar (asali). Wannan ikon na DNA to denaturation da renaturation kwayoyin tushen hybridization Hanyar. Ana amfani da a yi nazarin tsarin da nucleic acid.

Biyu-Helix kwayoyin, kasancewa m kayyade data, dole ne hadu biyu main bukatun. Da fari dai, ya kamata a replicated (reproduced) tare da high daidaituwa, kuma abu na biyu, to encode kira na gina jiki. Deoxyribonucleic acid, abin da samfurin da aka bayyana da Watson da Crick, yayi dace da cikakken to wadannan bukatun. An gano cewa, daidai da ka'ida na complementarity, kowane sarkar a cikin kwayoyin na iya zama da matrix da samuwar wani sabon yardatayya m kewaye. A sakamakon haka, daya mataki na kwafi haka ya auku ware 'yar kwayoyin ciwon nucleotide jerin m zuwa cewa a cikin na asali jigidar halittar DNA. Bugu da ƙari, wannan sarkar tsarin gene a shigar wanda ke aiki gina jiki amino acid jerin buga.

Tun da, kamar yadda aka sanya jama'a DNA bude da kuma complementarity manufa, kafa matakai da suke da alhakin hereditary dikodi mai data da kuma a cikin tsari na gene kira abubuwa. Bugu da kari, ka'idar da aka ɓullo da recombinant kwayoyin.