1 / 43

Structure of Bacteria

Structure of Bacteria. Size of Bacteria. Average bacteria 0.5 - 2.0 um in diam. RBC is 7.5 um in diam. Surface Area ~12 um^2 Volume is ~4 um Surface Area to Volume is 3:1 Typical Eukaryote Cell SA/Vol is 0.3:1 Food enters through SA, quickly reaches all parts of bacteria

rama-morgan
Download Presentation

Structure of Bacteria

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Structure of Bacteria

  2. Size of Bacteria • Average bacteria 0.5 - 2.0 um in diam. • RBC is 7.5 um in diam. • Surface Area ~12 um^2 • Volume is ~4 um • Surface Area to Volume is 3:1 • Typical Eukaryote Cell SA/Vol is 0.3:1 • Food enters through SA, quickly reaches all parts of bacteria • Eukaroytes need structures & organelles Chapter 4

  3. Shapes of Bacteria • Coccus • Chain = Streptoccus • Cluster = Staphylococcus • Bacillus • Chain = Streptobacillus • Coccobacillus • Vibrio = curved • Spirillum • Spirochete • Square • Star Chapter 4

  4. Chapter 4

  5. Chapter 4

  6. Chapter 4

  7. Chapter 4

  8. Chapter 4

  9. Bacterial Structures • Flagella • Pili • Capsule • Plasma Membrane • Cytoplasm • Cell Wall • Lipopolysaccharides • Teichoic Acids • Inclusions • Spores Chapter 4

  10. Flagella • Motility - movement • Swarming occurs with some bacteria • Spread across Petri Dish • Proteus species most evident • Arrangement basis for classification • Monotrichous; 1 flagella • Lophotrichous; tuft at one end • Amphitrichous; both ends • Peritrichous; all around bacteria • Observe Picture in Micro Lab. Chapter 4

  11. Chapter 4

  12. Mono- or Lophotrichorus Chapter 4

  13. Chapter 4

  14. Pili • Short protein appendages • smaller than flagella • Adhere bacteria to surfaces • E. coli has numerous types • K88, K99, F41, etc. • Antibodies to will block adherance • F-pilus; used in conjugation • Exchange of genetic information • Flotation; increase boyancy • Pellicle (scum on water) • More oxygen on surface Chapter 4

  15. F-Pilus for Conjugation Chapter 4

  16. Capsule or Slime Layer • Glycocalyx - Polysaccharide on external surface • Adhere bacteria to surface • S. mutans and enamel of teeth • Prevents Phagocytosis • Complement can’t penetrate sugars Chapter 4

  17. Cytoplasm • 80% Water {20% Salts-Proteins) • Osmotic Shock important • DNA is circular, Haploid • Advantages of 1N DNA over 2N DNA • More efficient; grows quicker • Mutations allow adaptation to environment quicker • Plasmids; extra circular DNA • Antibiotic Resistance • No organelles (Mitochondria, Golgi, etc.) Chapter 4

  18. Cell Membrane • Bilayer Phospholipid • Water can penetrate • Flexible • Not strong, ruptures easily • Osmotic Pressure created by cytoplasm Chapter 4

  19. Chapter 4

  20. Chapter 4

  21. Chapter 4

  22. Cell Wall Peptido-glycan Polymer (amino acids + sugars) Unique to bacteria Sugars; NAG & NAM N-acetylglucosamine N-acetymuramic acid D form of Amino acids used not L form Hard to break down D form Amino acids cross link NAG & NAM Chapter 4

  23. Chapter 4

  24. Chapter 4

  25. Chapter 4

  26. Chapter 4

  27. Chapter 4

  28. Chapter 4

  29. Cell Wall Summary • Determine shape of bacteria • Strength prevents osmotic rupture • 20-40% of bacteria • Unique to bacteria • Some antibiotics effect directly • Penicillin Chapter 4

  30. Video Clip on Cell Wall Chapter 4

  31. Teichoic Acids • Gram + only • Glycerol, Phosphates, & Ribitol • Attachment for Phages Chapter 4

  32. Chapter 4

  33. Lipopolysaccharide (LPS) Endotoxin or Pyrogen Fever causing Toxin nomenclature Endo- part of bacteria Exo- excreted into environment Structure Lipid A Polysaccharide O Antigen of E. coli, Salmonella G- bacteria only Alcohol/Acetone removes Chapter 4

  34. Chapter 4

  35. Chapter 4

  36. LPS (cont’d) • Functions • Toxic; kills mice, pigs, humans • G- septicemia; death due to LPS • Pyrogen; causes fever • DPT vaccination always causes fevers • Adjuvant; stimulates immunity • Heat Resistant; hard to remove • Detection (all topical & IV products) • Rabbits (measure fever) • Horse shoe crab (Amoebocytes Lyse in presence of LPS) Chapter 4

  37. LPS (cont’d.) • Appearance of Colonies • Mucoid = Smooth (lots of LPS or capsule) • Dry = Rough (little LPS or capsule) • O Antigen of Salmonella and E. coli • 2,000 different O Ags of Salmonella • 100’s different O Ags of E. coli • E. coli O157 • O Ags differ in Sugars, not Lipid A Chapter 4

  38. Endospores • Resistant structure • Heat, irradiation, cold • Boiling >1 hr still viable • Takes time and energy to make spores • Location important in classification • Central, Subterminal, Terminal • Bacillus stearothermophilus -spores • Used for quality control of heat sterilization equipment • Bacillus anthracis - spores • Used in biological warfare Chapter 4

  39. Chapter 4

  40. Chapter 4

  41. G+ vs. G- • G+ • Thicker cell wall • Teichoic Acids • G- • Endotoxin - LPS • Which are more sensitive to Penicllin? • Alcohol/Acetone affects which more? Chapter 4

  42. Prokaryotes vs. Eukaryotes • Cell Wall • Teichoic Acids • LPS • Endospores • Circular DNA • Plasmids Chapter 4

  43. Eukaryote Cell Structure Chapter 4

More Related