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Chapter 19

Bacteria and Viruses. Chapter 19. 1. Which of the following characteristics is NOT true of both Archaebacteria and Eubacteria ?. Unicellular All heterotrophic Prokaryotic Have cell walls. 2. Which bacterial kingdom lives in extreme habitats?. Archaebacteria Eubacteria.

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Chapter 19

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  1. Bacteria and Viruses Chapter 19

  2. 1. Which of the following characteristics is NOT true of both Archaebacteria and Eubacteria? Unicellular All heterotrophic Prokaryotic Have cell walls

  3. 2. Which bacterial kingdom lives in extreme habitats? Archaebacteria Eubacteria

  4. 3. What do you think the root “eu-” means? Nucleus New True Green

  5. Bacteria are the simplest and oldest life forms • fossils show bacteria that are 3.5 billion years old! • The oldest fossil evidence on earth is that of Archaebacteria. • Archaebacteria are believed to be the ancestors of both Eubacteria and the other eukaryotic kingdoms

  6. General Bacteria Structure Cell wall DNA Page 472

  7. Bacterial Shapes • Coccus – spherically shaped • Ex: Streptococcus • Bacillus – rod shaped • Ex: Clostridium botulinum • Spirillum – spiral shaped • Ex: Spirillum

  8. Arrangements of shapes • single cells or in groups • Diplo – two • Ex: Diplococcus (two spheres) • Strepto – in chains • Ex: Streptococcus (spheres in a chain) • Staphylo – in clumps • Ex: Staphylococcus (a clump of spheres)

  9. Name these bacterial cells:

  10. 4. What would be the name of this bacterial cell? • Diplobacillus • Streptococcus • Staphylococcus • Streptobacillus

  11. Draw the following bacterial cells: • Diplospirillum • Streptobacillus • Staphylococcus

  12. Bacteria and You • Foods made with bacteria: yogurt, cheese, sour cream • Decomposition • Bacteria are prevalent in sewage treatment plants, can be used to clean up oil spills, etc.

  13. Bacteria and You (cont) • Bacteria can be pathogenic (disease causing) • Can damage tissues (ex-Mycobacterium tuberculosis) or can release toxins (ex: Dental cavities and Streptococcus) • Antibiotics - compounds that block the growth and reproduction of bacteria • Penicillin – fungus that was the 1st antibiotic

  14. 5. Which bacterial kingdom do you think is “disease-causing”? • Archaebacteria • Eubacteria

  15. Viruses • poison in Latin • nonliving • don’t fulfill all criteria for life • must infect host cell to reproduce • lack enzymes for metabolism • don’t grow

  16. Virus Shape and Structure • Nucleic acid core • Capsid (protein coat) – gives the virus its shape

  17. How does a virus infect cells? • The virus recognizes a host cell at a specific receptor site. • The virus and host cell interlock like a puzzle; a lock and key • The virus then destroys the cell’s DNA and takes over metabolic functions • This specificity explains why each virus can only invade certain types of cells.

  18. Virus Examples • HIV – white blood cells • Polio- nerve cells • Adenovirus (cold virus)- adenoid tissue • Hepatitis- liver cells

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