BIO 191 Lecture Notes - Lecture 17: Transfer Rna, Spliceosome, Nonsense Mutation
4 Apr 2016
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Beadle and tatum worked on mold (neurospera) because it can survive in minimal media (salts, glucose, biotin) so it can grown. Looked for mutant mold that couldn"t make amino acids. Final conclusion: neurospora metabolic mutants that could not make arginine. Arginine was made from similar chemicals in the cell. Enzyme pathways: product of one enzyme is substate of next. 1 gene = 1 enzyme = 1 polypeptide. Cytoplasm is where protein is made, but the nucleus stores how the protein is made. Dna is transcribed to make rna (messenger rna, mrna) 2) polymerase initiates synthesis of rna with dna as the template. 3) pre-mrna is spliced and introns are removed. 4) mature mrna is exported from the nucleus. There are 43 combinations of the four bases, for 64 possible codons in the genetic code. Amino acids are coded in three-nucleotide words called codons (triplet cod) There are no spaces between words (soitallrunstogetehrlikethis) Got a polypeptide that was polyphenol alanine.
