01:119:115 Lecture Notes - Lecture 15: Archibald Garrod, George Beadle, Start Codon
27 Aug 2019
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Topic 15 - gene expression: experimental evidence. Genes are responsible for phenotypes through enzymes. Mendel"s principles of heredity applies to humans ! Genotype -> proteins -> phenotypes: experimental evidence. One enes -> one enzyme hypothesis: each gene = production of a specific enzyme. Now know that not all proteins are enzymes -> one gene -> one protein (actually polypeptide) Fracis crick (1956) proposed the central dogma. Transcription and translation occur in all organisms. Transcription : information in dna used to synthesize messenger rna (mrna) Translation: ribosomes use mrns to synthesize a polypeptide. In eukaryotes -> nuclear envelope + rna processing: rna composition and types. 1. mrna - messenger rna -> encodes an entire protein. 2. rrna - ribosomal rna -> structure part of a ribosome. 3. trna - transfer rna -> carry individual amino acids to ribosomes during translation: genetic code - codons: triplets of nucleotides. Proteins = 20 possible amino acids & peptide bonds.
