Ch 8
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  • http://www.nature.com/news/2010/100407/full/news.2010.169.html Interesting argicle on the results of transformation. Nick
  • The sum total of information carried by a cell, consists of chromosomes and extra chromosomal information Chromosome: The large DNA molecule of a bacterial cell that contains all the information/plans for the cell. Gene: a segment of DNA and its sequence of nucleotides that codes for a functional product, usually but not always a protein. Base pair: In the double helix structure each rung of this twisted latter is made of 2 nucleotides either AT or GC, These complementary base pairs make the replication of DNA possible. Each strand serves as a template for the other strand. Genetic code: the linear sequence of nucleotides that codes for specific RNA’s and proteins. For proteins each set of 3 nucleotides codes for a specific amino acid within the protein. Genotype: the genetic composition of an organism, its entire complement of DNA. Phenotype: the expression of an organisms genes: the protein of the cell and the properties they confer on the organism.
  • Polymer: a molecule consisting of a sequence of similar molecules, or monomers. Monomer: One of something, molecules of similar structure that are combined together to make a polymer. Polymers of life are: Proteins, Nucleic acids, Carbohydrates and lipids Why use polymers? The use of polymers allows cells to create incredibly complex molecules with complex functions with out having to create a multitude of different materials. Like the English language that is made up of about 26 sounds (Yes I know there are more). But the amount of information that is contained in our language and our communication is generated by those 26 sound.
  • A,G,T,C 20 amino acids make up the proteins
  • Replication: DNA Polymerase: DNA: DNA Transcription: RNA polymerase: DNA: RNA Translation: Ribosome's and various: RNA: Protein Reverse transcription: reverse transcriptase: RNA: DNA
  • What is sex and why is it important? Transformation: naked DNA is transferred between cells. Conjugation: F+ and f- cells. Transduction: phage used to move DNA about. Plasmids and Transposes.

Ch 8 Ch 8 Presentation Transcript

  • Microbial Genetics The how and why of information flow in living things. What exactly is living?
  • Genetics Terms
    • Genome:
    • Chromosome
    • Gene
    • Base pair
    • Genetic code
    • Genotype
    • Phenotype
  • The Polymers of life
    • Define Polymer
    • Define Monomer
    • What are the polymers of life?
    • Why use polymers?
  • Determine Relatedness Clinical Focus, p. 223
  • Determine Relatedness
    • Which strain is more closely related to the Uganda strain?
    Strain % Similar to Uganda Kenya 71% U.S. 51%
  • The genetic Code
    • Name the monomers that make up the genetic code.
    • Name the monomers that make up Proteins
  • What is the flow of genetic information in the bacterial cell? Verb Enzyme Substrate Product
  • Genetic Map of the Chromosome of E. coli Figure 8.1b
  • The Flow of Genetic Information Figure 8.2
  • DNA Replication
    • The double strand of DNA is separated.
    • DNA polymerase reads the DNA strand and creates another.
    • The newly synthesized DNA contains an old strand and a new strand.
    • The two new strands are then separated into the two new daughter cells.
  • Semiconservative Replication Figure 8.3a
  • DNA Synthesis Figure 8.4
  • DNA Synthesis
    • DNA is copied by DNA polymerase
      • In the 5'  3' direction
      • Initiated by an RNA primer
      • Leading strand is synthesized continuously
      • Lagging strand is synthesized discontinuously
      • Okazaki fragments
      • RNA primers are removed and Okazaki fragments joined by a DNA polymerase and DNA ligase
  • Transcription
    • A sequence of DNA is relaxed and opened up.
    • RNA polymerase synthesizes a strand of RNA
    • RNA uses ACGU
    • Starting point is a promoter
  • Transcription Figure 8.7
  • The Process of Transcription Figure 8.7
  • Translation
    • mRNA associates with ribosome's (rRNA and protein)
    • 3-base segments of mRNA specify amino acids and are called codons.
    • Genetic code: relationship among nucleotide sequence and corresponding DNA sequence.
  • Degenerate: Most amino acids are code for by more than one codon.
    • 64 codons
    • 3 are nonsense
    • Start codon Aug is for methionine.
    • See the codon sequence.
  • The Genetic Code Figure 8.8
  • Simultaneous Transcription & Translation Figure 8.10
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • The Process of Translation Figure 8.9
  • Info
    • From information storage to reality.
    • What determines what info is used
    • What determines how information is moved about.
  • Regulation
    • Constitutive genes are expressed at a fixed rate
    • Other genes are expressed only as needed
      • Repressible genes
      • Inducible genes
      • Catabolite repression
  • Operon Figure 8.12 ANIMATION Operons: Overview
  • Induction Figure 8.12
  • Induction Figure 8.12
  • Repression Figure 8.13
  • Repression Figure 8.13 ANIMATION Operons: Induction ANIMATION Operons: Repression
  • Catabolite Repression Figure 8.14 (a) Growth on glucose or lactose alone (b) Growth on glucose and lactose combined
    • Lactose present, no glucose
    • Lactose + glucose present
    Figure 8.15
  • Types of Bacterial sex Name Process What it is Comments
  • Genetic Recombination
    • The rearrangement of genes.
    • Crossing over is where genes are recombined within a chromosome.
  •  
  • Transformation
    • Naked DNA is transferred from one bacteria to another.
    • Was the first experiment that showed DNA was the genetic information
  • Genetic Recombination Figure 8.25
  • Genetic Transformation Figure 8.24 ANIMATION Transformation
  • Conjugation
    • DNA transferred from one bacteria to another by a sex pillus.
    • Information of transfer coded by a plasmid called F+
    • Hfr cells occur when F+ plasmid goes into the host chromosome and recombines, it will then draw across the DNA.
  • Bacterial Conjugation Figure 8.26
  • Conjugation in E. coli Figure 8.27a
  • Conjugation in E. coli Figure 8.27b
  • Conjugation in E. coli Figure 8.27c
  • Transduction
    • DNA is passed from one bacterium to another in a bacteriophage and put into recipients DNA.
  • Transduction by a Bacteriophage Figure 8.28
  • Alternate forms of the chromosome format.
    • Plasmids: self replicating circular molecules of NDA
    • Transposes: small segments of DNA that can move into different parts of the genome.
    • Can these have an effect on Evolution?
  • Control of gene expression
    • Repression
    • Induction
  •  
  • The Operon Model of gene expression
    • Repression: regulatory mechanism inhibits gene expression
    • Induction: a process that turn on gene expression
  • Repressible Operon
  • Inducible operon
  • Where are the points of control
  • If a cell has all the genes that are needed then why are they not expressed at one time?
  •  
  • Mutations
    • What are they?
  • Mutations
    • What can they do
  • Mutation
    • A change in the genetic material
    • Mutations may be neutral, beneficial, or harmful
    • Mutagen: Agent that causes mutations
    • Spontaneous mutations: Occur in the absence of a mutagen
    • Base substitution (point mutation)
    • Missense mutation
    Mutation
    • Change in one base
    • Result in change in amino acid
    Figure 8.17a, b
    • Nonsense mutation
    Mutation
    • Results in a nonsense codon
    Figure 8.17a, c
  • Mutation
    • Frameshift mutation
    • Insertion or deletion of one or more nucleotide pairs
    Figure 8.17a, d
  • The Frequency of Mutation
  • Chemical Mutagens Figure 8.19a
  • Radiation
    • Ionizing radiation (X rays and gamma rays) causes the formation of ions that can react with nucleotides and the deoxyribose-phosphate backbone
  • Radiation
    • UV radiation causes thymine dimers
    Figure 8.20
  • Repair
    • Photolyases separate thymine dimers
    • Nucleotide excision repair
    Figure 8.20
  • Selection
    • Positive (direct) selection detects mutant cells because they grow or appear different
    • Negative (indirect) selection detects mutant cells because they do not grow
      • Replica plating
  • Replica Plating Figure 8.21
  • Ames Test for Chemical Carcinogens Figure 8.22
  •  
  •  
  • The old and new genetics
    • Screening and selection of mutants
  •  
  • What do you think we would call the new genetics?