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Guyton Question anyone.........

Discussion in 'Step I' started by naveenanirada, Nov 19, 2005.

  1. naveenanirada

    naveenanirada Member
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    Hi folks,

    Guyton, chapt.3, pg.31 has a table = 3.1

    It says RNA;CODONS FOR AMINOACIDS AND FOR START AND STOP

    The text says = table 3.1 gives the RNA codons for the 20 common amino acids found in protein molecules.Note that most of the amino acids are represented by more than one codon, also one codon represents the signals ' start manufacturing a protein molecule ' .

    ==================================================
    Please find the table 3.1 below
    AMINO ACID RNA CODONS
    Alanine GCU GCC GCA GCG
    Arginine CGU CGC CGA CGG
    Asparagine AAU AAC
    Aspartic acid GAU GAC
    Cystine UGU UGC
    Glutamic acid GAA GAG
    Glutamine CAA CAG
    Glycine GGU GGC GGA GGG
    Histidine CAU CAC
    Isoleucine AUU AUC AUA
    Leucine CUU CUC CUA CUG
    Lysine AAA AAG
    Methionine AUG
    Phenylalanine UUU UUC
    Proline CCU CCC CCA CCG
    Serine UCU UCC UCA UCG
    Threonine ACU ACC ACA ACG
    Tryptophan UGG
    Tyrosine UAU UAC
    Valine GUU GUC GUA GUG

    ================================================
    What do the codons represent?Do multiple codons reprsent the samr AAcid?
    Would appreciate any help in understanding the above table and text.
    Regards and cheers
    NN
     
  2. bhuvi

    bhuvi Junior Member
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    There are total 64 codons, all written in 5' --3' direction. 61 codons encode for the aminoacids and 3 i.e, UAA, UGA, UAG are stop codons.
    AUG is the start codon, methionine in eukaryotes, formyl meth in prokaryotes.

    Codon is unambigious.. ie each codon for not >1 aa
    Codon is degenerate.. >1 codon for all aa, except for meth(AUG) and tryptophan(UGG)
    Codon is universal, same in all organisms


    Hope this helps1
     
  3. naveenanirada

    naveenanirada Member
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    Thanks BHUVI,thanks a bunch.
     

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