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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation Viruses: Genes in Small Packages
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Central Dogma of Biology: How Shape and Form Are Dictated By DNA Genes A segment of DNA (gene) carries specific coded instructions for the making of a single proteins. Genotype: The genes carried in a cell for a particular trait Phenotype: The physical expression of genes for a particular trait
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Transcription: From DNA to RNA In transcription, –Genetic information is transferred from DNA to RNA. –An RNA molecule is transcribed from a DNA template. Transcription
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Figure 10.14 In Eukaryotes, the mRNA is Edited Before Leaving the Nucleus
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation and Mutagens Viruses: Genes in Small Packages
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= 3 Types of RNA – Each With a Different Job Messenger RNA (mRNA) Carries copy of gene information to the ribosome to make protein anticodon Ribosomal RNA (rRNA) Part of the structure of the ribosome; key component in amino acid linking machinery CUG Transfer RNA (tRNA) Carries amino acids to the ribosome for linking; identified by anticodon “sign”
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation and Mutagens Viruses: Genes in Small Packages
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Figure 10.17 Anatomy of a Messenger RNA Leader Trailer
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How Gene Instructions are Communicated
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mRNA Codon Dictionary of the Genetic Code
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DNA template strand: CGTTTACGACCGGCCTTAGATCCTGACG Central Dogma: DNA RNA Protein mRNA: GCAAAUGCUGGCCGGAAUCUAGGACUGC Transcription by RNA polymerase Translation by ribosome Protein: Met -Leu -Ala -Gly -Ile
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Figure 10.16a
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Figure 10.16b
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation and Mutagens Viruses: Genes in Small Packages
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Translation: The Process Translation is divided into three phases: –Initiation –Elongation –Termination
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Translation: Initiation Events of Initiation 1.The messenger RNA binds to the small ribosomal subunit 2.The two subunits of the ribosome come together 3.The first amino acid with its attached tRNA
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Translation: Elongation Events of Elongation –1. The anticodon of an incoming tRNA pairs with the mRNA codon. 2. The ribosome catalyzes a peptide bond to form between amino acids 3. A tRNA leaves the P site of the ribosome 4. The ribosome moves down the mRNA (translocation)
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Translation: Termination Events of Termination 1.Elongation continues until the ribosome reaches a stop codon. 2.The two subunits of the ribosome separate 3.The mRNA is released to be used again 4.The finished polypeptide (protein) folds up and begins functioning
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Figure 10.10
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Review: DNA RNA Protein The flow of genetic information in a cell
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation Viruses: Genes in Small Packages
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Mutations A mutation –Is any change in the nucleotide sequence of DNA –Is a permanent, heritable change Mutations may result from –Errors in DNA replication. –Physical or chemical agents called mutagens. Although mutations are usually lethal, –They are the source of the rich diversity of genes in the living world. –They contribute to the process of evolution by natural selection.
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Figure 10.21 Base Substitution (Point Mutation) DNA base substitutions can cause: missense, run-on, nonsense, and silent mutations in the resultant protein
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Figure 10.22b Insertions or Deletions of DNA nucleotides Insertion/Deletions cause frameshift mutations in the protein (and often run-on mutations too)
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Types of Mutation
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation and Mutagens Viruses: Genes in Small Packages
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Viruses: Genes in Packages Properties of Viruses –They exhibit some, but not all, characteristics of living organisms –They are made of DNA or RNA surrounded by a protein coating. Some also have envelopes outside their protein coat –They are incredibly small (< 1 um) –They are obligate intracellular parasites –They they can only attack a small range of cell types (host specificity)
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Viruses Come in Many Shapes Helical Polyhedral Enveloped Complex
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Figure 10.26 Bacterial Viruses Can Either Reproduce Immediately or Hide Within The Host Cell and Emerge When the Host is Dying
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Animal Viruses Often Have a Membranous Envelope with Protein Spikes The influenza virus carries specific “spikes” that make them infective Spikes are classified by Hemagglutinin (H) and Neuraminidase (N) types e.g. H1N1
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Figure 10.29 Simplified Viral Reproductive Cycle Animal Virus Lifecycle
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HIV, the AIDS Virus HIV is a retrovirus. –A retrovirus is an RNA virus that reproduces by means of a DNA molecule. –It copies its RNA to DNA using reverse transcriptase. HIV Reproductive Cycle
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Figure 10.30b How Human Immunodeficiency Virus Attacks T White Blood Cells
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The Structure and Function of DNA CHAPTER 10 Transcription (DNA RNA) RNA Polymerase Processing of Eukaryotic RNA Translation (mRNA Protein) The Three Types of RNA Codons and the Genetic Code Ribosomes Steps of Translation Mutation Viruses: Genes in Small Packages
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