BIOL 240 1st Edition Lecture 22Outline of Last Lecture I. Genes and metabolic pathwaysII. Systematic mutational analysis of metabolic pathways in NeurosporaIII. Disease mutationsIV. Amino acidsOutline of Current Lecture I. Post-translational ModificationsII. Gene ExpressionIII. DNA vs. RNAIV. TranscriptionV. Prokaryotic PromotersCurrent LectureI. Post-translational Modifications- Amino acids can be covalently modified by the attachment of different chemical groups- Phosphorylation—most common; phosphate group is added; occurs at OH groups…so serine, threonine, and tyrosine- Protein kinase—enzymes that phosphorylate proteins- Protein phosphatases—enzymes that dephosphorylate proteinsII. Gene Expression- Prokaryoteso Transcription and translation happen simultaneouslyo Primary transcripts not processed furthero Many transcripts encode multiple polypeptides- Eukaryoteso Transcripts made in nucleus and transported to cytoplasm to be translatedo Primary transcripts processed before being transportedo Most transcripts encode a single polypeptideIII. DNA vs. RNAThese 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.- RNAribose base (1 extra OH group)- RNA has uracil instead of thymine- Only one of the 1 DNA strands serves as a template for RNA synthesisIV. Transcription- DNA is fed through RNA polymerase and unwinds- DNA strand with gene 1 is used as a template for RNA strand- DNA rewinds- DNA strand with gene 2 is used as a template for RNA strand (could be opposite strand than used for gene 1)- Unwound DNA is fed through RNA polymerase to rewind- RNA “pieces” are added at the 3’ end of the growing RNA chainV. Prokaryotic Promoters- DNA sites where RNA polymerase binds and initiates transcription- Transcription initiates at the +1 site- Promoter function regulated by transcription
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