BIOLCHEM 415 1st Edition Lecture 37Outline of Last Lecture I.Mature Ribosomal RNA generated by the cleavage of precursor mRNAII. tRNA is extensively processedIII. mRNA is modified and splicedIV. RNA can functions as a catalystOutline of Current Lecture V. The genetic code links nucleic acid and protein informationVI. Amino acids are activated by attachment to tRNAVII. A ribosome is a ribonucleoprotein particle made of two subunits Current LectureGenetic Code- 3 nucleotides (codon) = amino acids (eukaryotes begin with AUG)- non-overlapping code- no internal punctuation- direction (5’3’)- degenerate- some amino acids coded by >1 codon- 2 unique ones (Met (AUG) and Trp (UGG))- 43 codons (to code for 20 amino acids)- universal- most organisms use same- those with modified branched early in evolution- mitochondriaThese 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.Mutations and human disease- Ras mutations in cancer (lung, pancreatic, colon)- missense mutation = codes for different amino acidsTransfer RNA molecules (tRNA)- adaptor between codon and amino acid- cloverleaf 2D structure and L-shaped 3D structure- wobble – greater degree of pairing of 3rd base of codon with 1st base anticodon- rapid dissociation during protein synthesisSynthesis of long proteins require low error frequency- ~10-4 means accurate synthesisAmino acid activated by tRNA attachment- amino-acyl tRNAAminoacyltRNAsynthetases- highly discriminatory- editing sitesTranslation catalyzed by ribosomes- protein synthesis at ribosomeCo-transcriptional translation in bacteria - not separated because there is no nuclear
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