NEET AIPMT SOLVED PAPER SCREENING 2009

  • question_answer
    Whose experiments cracked the DNA and discovered unequivocally that a genetic code is a triplet?

    A) Nirenberg and Mathaei

    B) Hershey and Chase

    C) Morgan and Sturtevant

    D) Beadle and Tatum

    Correct Answer: A

    Solution :

    The existence of triplet code was simply an assumption till 1961, when Nirenberg and Methaei proved its existence by experiments. They were able to synthesize artificial mRNA, which contained only one nitrogenous base, ie, uracil. This synthetic poly U sequence was then placed in a cell free system containing protein synthesizing   enzymes   (extracted   from bacterium E. coli) and 20 amino acids together with necessary ATP. During the process, a small polypeptide molecule was produced, which was formed by the linking of phenylalanine. This suggested that UUU is the code for phenyl alanine. Nirenberg got Nobel Prize for his contributions.


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