Biology 135A Gene Expression (Ch. 17) Lecture Notes PDF

Biology 135A Gene Expression (Ch. 17) Rajab Outline Discovery of genes and the genetic code Transcription RNA modification Translation  Intro to transcription and translation  The Genetic Code Triplet code → 64 codons Template and nontemplate (coding) DNA strand...

Biology 135A Gene Expression (Ch. 17) Rajab Outline Discovery of genes and the genetic code Transcription RNA modification Translation  Intro to transcription and translation  The Genetic Code Triplet code → 64 codons Template and nontemplate (coding) DNA strands mRNA is made and translated in 5’ →3’ direction  Genetic code 61 AA codons including START codon 3 stop codons Degenerate→ synonymous codons Universal  Reading frame KGHTTYULKEYILWRKHRDFORNXTTSTWLLPAYOFFHGTYIL WRK HDF ORN XTT STW LLP AYO FF [deletion of R] Transcription-Overview  Transcription Initiation  Transcription Elongation 5’→3’ 40 nucleotides/sec Transcription Termination Bacteria → terminator sequence Eukaryotes → pol II transcribes poly A signal (AAUAAA) which attracts proteins that then cut the RNA off from the polymerase about 10-35 bp downstream from the poly A signal https://www.youtube.com/watch?v=WsofH466lqk  Eukaryotic RNA Processing Capping and tailing Export Protection Translation initiation  Eukaryotic RNA Processing Splicing Introns Exons Spliceosome Exon-domain relationship  Alternative splicing How just 20,000 genes can produce hundreds of thousands of proteins Translation-overview Major players: mRNA tRNA Amino acids Aminoacyl tRNA synthetases Ribosomes Polypeptide  tRNA Single-stranded Acceptor stem Anticodon #AA