MIMM 211 Lecture Notes - Lecture 12: Transfer Rna, Pyrimidine Dimer, Exonuclease
13 Dec 2018
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Document Summary
The dna sequence (4nts) needs to code for 20 different aas. A codon cannot be shorter than 3 nucleotides in length. The code is degenerate there is more than one codon for each aa (up to 6) 2 aas have only 1 codon: trp and met. There are 61 sense codons and 3 stop codons (nonsense codons) There are not 61 different 6trnas bc of the wobble (loose pairing) pairing between the codon (mrna) and anticodon (trna) during translation: there are 45-47 trnas in e. coli rather than 61 (for example) Degeneracy usually, the first two letters of the codon will be the same and only the letter in the third position will change. This is how the enzymes can read multiple codons. Codon anticodon recognition by t-rna trna"s secondary structure is often called a cloverleaf structure. Called transfer rna because they transfer the information coming from the mrnas into aa sequences (to form proteins)
