BCHM 4116 1st Edition Lecture 29 Outline of Last Lecture 1 Eukaryotic Transcripts Processed and Delivered to Ribosome for Translation Outline of Current Lecture 1 Protein Synthesis 2 Genetic Code Current Lecture Chapter 30 Protein Synthesis 1 30 1 Genetic Code a Triplet code group of 3 bases codes for 1 amino acid b Not overlapping c If reading frame is displace by 1 base shifted throughout d Condon represent triplets of bases in mRNA i Degenerate each AA can be coded by any of several triplets ii Meaning 3 nonsense codons UAA UAG UGA 1 serve as termination codons Stop signals indicating end of protein iii Unambiguous each 61 sense codons encodes only 1 AA iv Codons representing the same AA or chemically similar AA tend to be similar in sequence 1 Third base degeneracy often 3rd base in codon is irrelevant v Universal 1 Conformity means that all extant organisms use same genetic code strong evidence that they all evolved from a common primordial ancestor 2 30 2 AA matched with proper tRNA a Appropriate tRNAs have anticodons that can base pair w codons specifying particular AA b Aminoacyl tRNA synthetase catalyzes ATP dependent attachment of its specific AA to the 3 end of its cognate tRNA molecule c Aminoacyl tRNA synthetase serves 2 purposes i Activates AA so that it will readily react to form a peptide bond ii Bridges the info gap b w AA and codons d 2 distinct classes of aminoacyl tRNA synthetases i Class 1 adds AA to 2 OH of terminal adenylate residue of tRNA before shifting it to 3 OH These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 1 Bind tRNA acceptor stem helix from minor groove side ii Class 2 adds directly to 3 OH 1 Binds tRNA acceptor stem helix from major groove side e Anticodon stem interacts w mRNA template
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