BMS1062 Lecture Notes - Lecture 6: Cytosine, Reading Frame, Pyrimidine
14 Aug 2018
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Remember that mrna has no affinity for aa, but its bases are complementary to trna) The unit of code specifying a single amino acids = codon (triplet bp) Why the use of a codon? there are 4 types of nucleotides. 43 possibilities for amino acids, 42 wouldn"t be enough. Codon identification -> the codons do not overlap. Codon identification using mrnas using translated mrnas in vitro: Codon identification using copolymers eg: using the dinucleotide ca (cytosine - adenine) While aca -> his gives thr-his-thr-his hence it can be concluded that cac codon -> thr eg: using the trinucleotide caa. Caacaacaacaacaa gives asn-asn-asn-asn-asn or thr-thr-thr-thr-thr-thr or gln-gln-gln-gln-gln depending on the reading frame thus it can be reasonably concluded that. The genetic code ( note that the start codon is also the codon for methionine) Biases, as in humans might prefer to use a specific codon when compared with a prokaryote.
