821 wobble some trnas recognize more than one codon

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Unformatted text preview: and protein. Fig. 8.23 Initiation sets stage for polypeptide synthesis. Mechanism of translation AUG start codon at 5' end of mRNA Formalmethionine (fMet) on initiation tRNA First amino acid incorporated in bacteria Elongation during which amino acids are added to growing polypeptide Ribosomes move in 5'-3' direction revealing codons. Addition of amino acids to C terminus 2-15 amino acids per second Nonsense codon recognized at 3' end of reading frame Release factor proteins and halt polypeptide synthesis Termination which halts polypeptide synthesis Initiation of translation Fig. 8.24 a Elongation Fig. 8.24 b Termination of translation Fig. 8.24 c Posttranslational processing can modify polypeptide structure. Fig. 8.25 Significant differences in gene expression between prokaryotes and eukaryotes Eukaryotes, nuclear membrane prevents coupling of transcription and translation. Prokaryotic messages are polycistronic. Contain information for multiple genes Eukaryotes, small ribosomal subunit binds to 5' methylated cap and migrates to AUG start codon. 5' untranslated leader sequence between 5' cap and AUG start Only a single polypeptide produced from each gene Initiating tRNA in prokaryotes is fMet. Initiating tRNA in eukaryotes Met is unmodified. A computerized analysis of gene...
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This note was uploaded on 08/04/2009 for the course BIOL 2153 taught by Professor Larkin during the Fall '03 term at LSU.

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