Kalli nassi da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar nassi: Nassi: Kwayar halittar da aka ba da ita ta ƙunshi dubban kwayoyin halitta, amma ba duk waɗannan kwayoyin halittar suna buƙatar yin aiki a kowane lokaci ba. Ana bayyana kwayar halitta lokacin da ake fassara shi zuwa mRNA kuma akwai hanyoyin salula da yawa na sarrafa maganganun kwayoyin halittar kamar yadda ake samar da sunadarai kawai lokacin da kwayar ke buƙata. Abubuwan da ke tattare da kwayar halitta sune sunadarai masu sarrafawa waɗanda ke ɗaure zuwa DNA, ko dai inganta ko hana fassarar kwayar halitta. A cikin kwayar halittar kwayoyin Escherichia coli, alal misali, akwai jerin kwayoyin halittar da ake buƙata don haɗuwa da amino acid tryptophan. Koyaya, lokacin da tryptophan ya riga ya kasance ga kwayar halitta, waɗannan kwayoyin halittar don haɗin tryptophan ba a buƙata. Kasancewar tryptophan kai tsaye yana shafar ayyukan kwayoyin halittar kwayoyin halittar don hana tryptophan (mai), canza tsarin tsarin kwayar halittar kwayoyin halittar da
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