1/18/2016 RNA processing in eukaryotic cells Exon Intron Exon Intron Exon DNA RNA mRNA o After further modification,the mature mRNA Nucleus Cytoplasm Translation:The Second Stage of Gene Language of mRNA Expression Involves the decoding of the "language"of ·和emg0服n油地8X88 nucleic acids into the "language"of proteins Sequence of the codon determines the All of the elements needed to synthesize a amino acid sequence of the protein to be protein are brought together on the synthesized ribosomes Genetic Code:each codon encodesa ·Three stages particular amino acid Genetic code is universal 1.initiation Genetic code is redundant 2.elongation 3.termination 91/18/2016 9 RNA processing in eukaryotic cells RNA polymerase DNA Met Met Met DNA Exon Intron Exon Intron Exon 1In the nucleus, a gene composed of exons and Insert Fig 8.11 1 Met Met introns is transcribed to RNA by RNA polymerase RNA transcript mRNA 2 Processing involves snRNPs in the nucleus to remove the intron-derived RNA and splice together the exon-derived RNA into mRNA. 3 After further modification, the mature mRNA travels to the cytoplasm where it directs protein Nucleus Cytoplasm travels to the cytoplasm, where it directs protein synthesis. Translation: The Second Stage of Gene Expression • Involves the decoding of the “language” of nucleic acids into the nucleic acids into the language of proteins “language” of proteins • All of the elements needed to synthesize a protein are brought together on the ribosomes • Three stages: 1. initiation 2.elongation 3.termination Language of mRNA • In the form of codons, which are groups of three nucleotides, such as AUG, AAA, GGC • Sequence of the codon determines the amino acid sequence of the protein to be synthesized • Genetic Code: each codon encodes a particular amino acid • G ti ene c code i i l is universal • Genetic code is redundant