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Microbial Genetics

Microbial Genetics

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Microbial Genetics

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  1. Microbial Genetics The how and why of information flow in living things. What exactly is living?

  2. Genetics Terms • Genome: • Chromosome • Gene • Base pair • Genetic code • Genotype • Phenotype

  3. The Polymers of life • Define Polymer • Define Monomer • What are the polymers of life? • Why use polymers?

  4. Determine Relatedness Clinical Focus, p. 223

  5. Determine Relatedness Which strain is more closely related to the Uganda strain?

  6. The genetic Code • Name the monomers that make up the genetic code. • Name the monomers that make up Proteins

  7. What is the flow of genetic information in the bacterial cell?

  8. Genetic Map of the Chromosome of E. coli Figure 8.1b

  9. The Flow of Genetic Information Figure 8.2

  10. 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.

  11. Semiconservative Replication Figure 8.3a

  12. DNA Synthesis Figure 8.4

  13. 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

  14. 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

  15. Transcription Figure 8.7

  16. The Process of Transcription Figure 8.7

  17. 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.

  18. 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.

  19. The Genetic Code Figure 8.8

  20. Simultaneous Transcription & Translation Figure 8.10

  21. The Process of Translation Figure 8.9

  22. The Process of Translation Figure 8.9

  23. The Process of Translation Figure 8.9

  24. The Process of Translation Figure 8.9

  25. The Process of Translation Figure 8.9

  26. The Process of Translation Figure 8.9

  27. The Process of Translation Figure 8.9

  28. The Process of Translation Figure 8.9

  29. Info • From information storage to reality. • What determines what info is used • What determines how information is moved about.

  30. Regulation Constitutive genes are expressed at a fixed rate Other genes are expressed only as needed Repressible genes Inducible genes Catabolite repression

  31. Operon ANIMATION Operons: Overview Figure 8.12

  32. Induction Figure 8.12

  33. Induction Figure 8.12

  34. Repression Figure 8.13

  35. Repression ANIMATION Operons: Induction ANIMATION Operons: Repression Figure 8.13

  36. Catabolite Repression (a) Growth on glucose or lactose alone (b) Growth on glucose and lactose combined Figure 8.14

  37. Lactose present, no glucose Lactose + glucose present Figure 8.15

  38. Types of Bacterial sex

  39. Genetic Recombination • The rearrangement of genes. • Crossing over is where genes are recombined within a chromosome.

  40. Transformation • Naked DNA is transferred from one bacteria to another. • Was the first experiment that showed DNA was the genetic information

  41. Genetic Recombination Figure 8.25

  42. Genetic Transformation ANIMATION Transformation Figure 8.24

  43. 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.

  44. Bacterial Conjugation Figure 8.26

  45. Conjugation in E. coli Figure 8.27a

  46. Conjugation in E. coli Figure 8.27b

  47. Conjugation in E. coli Figure 8.27c

  48. DNA is passed from one bacterium to another in a bacteriophage and put into recipients DNA. Transduction

  49. Transduction by a Bacteriophage Figure 8.28