Basic Principles of Transcription and Translation - Computer ...

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Elongation of the RNA Strand As RNA polymerase moves along the DNA, it untwists the double helix, 10 to 20 bases at a time Transcription progresses at a rate of 40 nucleotides per second in eukaryotes A gene can be transcribed simultaneously by several RNA polymerases Termination of Transcription The mechanisms of termination are different in bacteria and eukaryotes In bacteria, the polymerase stops transcription at the end of the terminator In eukaryotes, the polymerase continues transcription after the pre-mRNA is cleaved from the growing RNA chain; the polymerase eventually falls off the DNA
Eukaryotic cells modify RNA after transcription Enzymes in the eukaryotic nucleus modify pre-mRNA before the genetic messages are dispatched to the cytoplasm During RNA processing, both ends of the primary transcript are usually altered Also, usually some interior parts of the molecule are cut out, and the other parts spliced together Alteration of mRNA Ends Each end of a pre-mRNA molecule is modified in a particular way: The 5′ end receives a modified nucleotide 5′ cap The 3′ end gets a poly-A tail These modifications share several functions: They seem to facilitate the export of mRNA They protect mRNA from hydrolytic enzymes They help ribosomes attach to the 5′ end
Page 1 and 2: The Flow of Genetic Information Th
Page 3 and 4: TRANSCRIPTION DNA mRNA (a) Bacteria
Page 5 and 6: The Genetic Code How are the instr
Page 7 and 8: Cracking the Code All 64 codons we
Page 9 and 10: Molecular Components of Transcripti
Page 11: RNA Polymerase Binding and Initiati
Page 15 and 16: 5′ Exon Intron Exon Intron Pre-mR
Page 17 and 18: The Functional and Evolutionary Imp
Page 19 and 20: Polypeptide Trp Phe Ribosome Amino
Page 21 and 22: Amino acid P P P ATP Adenosine Amin
Page 23 and 24: Building a Polypeptide The three s
Page 25 and 26: The elongation cycle of translation
Page 27 and 28: Growing polypeptides Completed poly
Page 29 and 30: Polypeptide synthesis always begins
Page 31 and 32: Type of RNA Small nucleolar RNA (sn
Page 33 and 34: RNA polymerase RNA polymerase Polyr
Page 35 and 36: Individual bacteria respond to envi
Page 37 and 38: Eukaryotic gene expression can be r
Page 39 and 40: CYTOPLASM mRNA in cytoplasm Degrada
Page 41 and 42: Histone tails DNA double helix Amin
Page 43 and 44: Epigenetic Inheritance Although th
Page 45 and 46: The Roles of Transcription Factors
Page 47 and 48: Mechanisms of Post-Transcriptional
Page 49 and 50: Initiation of Translation The init
Page 51 and 52: Noncoding RNAs play multiple roles
Page 53: Chromatin Remodeling and Silencing

Basic Principles of Transcription and Translation - Computer ...

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