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Bacterial Classification, Structure, and Physiology Overview

Learn about Archaebacteria & Eubacteria, Gram Staining, Cell Structure, Nutrition, Disease, Antibiotics, Replication, and Useful Bacteria in this comprehensive chapter. Explore key concepts and characteristics of different bacterial groups.

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Bacterial Classification, Structure, and Physiology Overview

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  1. Bacteria Chapter 24

  2. Classification • Structure • Physiology • Molecular composition • Reactions too stain • rRNA sequences

  3. Archaebacteriaaka: ancient bacteria • Unusual lipids in cell membrane- no petoglycan • Introns in DNA • Cell walls lack peptidoglycan • Genes closely related to early eukaryotes • Extreme environments

  4. Archaebacteria

  5. Archaebacteria • Methanogens • Convert H2 and CO2 into methane gas • Live in anaerobic environment • Found in intestinal tracts of humans and other animals • Extreme halophiles • Salt lovers • Use salt to generate ATP • Found in Dead Sea

  6. Archaebacteria • Thermoacidophiles • Live in acidic environments pH <2 • Live in high temperatures up to 230 • Live near volcanic vents and cracks in the ocean floor

  7. Gram stainingpg 471 • Gram-positive - appear purple under a microscope • Thicker peptoglycan • Causes different resistance to antibiotics • Produce different toxins • Gram-negative - do not retain stain appearing pink under a microscope

  8. Gram Staining

  9. Eubacteriaaka: new bacteria • Three basic shapes • cocci • bacilli • Spirilla • Strepto= Chains • Staphlo= Grape like clusters • 12 different phyla according to evolutionary relationships

  10. Cocci

  11. Bacilli

  12. Spirilla

  13. Eubacteria • Cyanobacteria • Autotrophic • Makes its own food • Photosynthetic • “Blue-green algae” • Often cling in colonies • Thrive on nitrates and phosphates in a body of water • Population bloom or eutrophication

  14. Cynobacteriaaka: blue green algae

  15. Eubacteria • Spirochetes • Gram-negative • Spiral shaped • Heterotrophic • Cannot make its own food • Example- Treponema pallidium (Syphilis)

  16. Spirochetes

  17. Eubacteria • Gram-Positive Bacteria • Not all are gram-positive • Cause tooth decay • Turn milk into yogurt • Causes strep throat

  18. Eubacteria • Proteobacteria- largest most diverse group • Enteric bacteria • inhabit animal intestines (E. Coli) • Chemoautotrophic • Gram-negative bacteria • Oxidizes chemicals • Nitrogen-fixing bacteria • Convert nitrogen into ammonia

  19. E. Coli

  20. Nitrogen-fixing Bacteriapg 467-475

  21. Structure • Cell Wall • Eubacteria - peptidoglycan • Cell Membrane • Acts like mitochondria in cells • Contains enzymes that speed up cellular respiration • Cytoplasm • Contains DNA, ribosomes, & organic compounds

  22. Structure • Capsules • Outer covering that protects the cell and assist in attaching the cell to other surfaces • Pili- used for adhesion • Hairlike protein structures that transfer genetic material from one bacterium to another • Endospores • Dormant structure protecting against harsh conditions • When conditions are right, bacteria emerge.

  23. Yogurt

  24. Nutrition and Growth • Saprophytes - feed on dead and decaying material • Photoautotrophic – uses the sun to make its own food (blue-green algae) • Obligate anaerobe - cannot live in presence of oxygen (Tetnus) • Facultative anaerobe - Can live with or without oxygen (E.coli)

  25. Nutrition and Growth • Obligate aerobes - Cannot live without oxygen (Turberculosis) • Thermophilic - Grow between 104 - 230

  26. Bacteria and Disease • Pathology - Studying diseases • Toxins = poisons • Exotoxins = Toxins made of proteins (Gram-Positive Bacteria) • Endotoxins = Toxins made of lipids and carbohydrates (Gram-Negative Bacteria) • Not released till bacteria die • Cause fever, aches, weakness

  27. Antibiotics • Combat bacteria by interfering with various cellular functions • Resistance • Mutated bacteria that is resistant to antibiotics can continue to grow and reproduce Example- Penicillin attacks bacteria cell walls

  28. Body’s Defense

  29. Useful Bacteria • Insecticides • Clean up environmental disasters • Produce and process food • Turn sewage into simpler organic compounds

  30. Bacteria Replication

  31. Binary fission • Divides a prokaryotic cell into 2 off spring cells

  32. Binary fission cont. • DNA is copied

  33. Binary fission cont. • Cell begins to divide

  34. Binary fission cont. • Two identical haploid cells (original # of chromosomes)

  35. Binary Fission

  36. More terms to know • Population bloom • Capsule • Saprophytes • Pathogen • Conjugation • 2 bacteria connect and transfer genetic material to each other.

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