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Chapter 19

Bacteria and Viruses. Chapter 19. Complete the top left portion of the graphic organizer, recording the Characteristics of Kingdom Archaebacteria and Kingdom Eubacteria. Include the Cell Type, Cellular Organization, Mode of Nutrition, Cell Wall Component and Habitat.

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Chapter 19

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  1. Bacteria and Viruses Chapter 19

  2. Complete the top left portion of the graphic organizer, recording the Characteristics of Kingdom Archaebacteria and Kingdom Eubacteria. Include the Cell Type, Cellular Organization, Mode of Nutrition, Cell Wall Component and Habitat.

  3. Record the answers to the following questions on the back of your paper:1. Which of the following characteristics is NOT true of both Archaebacteria and Eubacteria? Unicellular All heterotrophic Prokaryotic Have cell walls

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

  5. 3. What does the root “eu-” mean? Nucleus New True Green

  6. 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

  7. peptidoglycan Cell wall DNA Page 472

  8. Bacteria are categorized according to their shape and arrangement.Bacterial Shapes: • Coccus – spherically shaped • Ex: Streptococcus • Bacillus – rod shaped • Ex: Clostridium botulinum • Spirillum – spiral shaped • Ex: Spirillum

  9. 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)

  10. On the back of your paper, Identify these bacterial cells: 4. 5.

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

  12. On the back of your paper, draw the following bacterial cells: 7. Diplospirillum 8. Streptobacillus 9. Staphylococcus

  13. Bacteria and You – Good uses • 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. • Digestion

  14. Bacteria and You (cont) • Bacteria can be pathogenic (disease causing) – Not Good! • 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 – 1st antibiotic

  15. Record your answer on the back of your paper 10. Which bacterial kingdom is “disease-causing”? • Archaebacteria • Eubacteria

  16. Viruses • Virus = poison in Latin • Viruses are nonliving • Don’t fulfill all criteria for life. Viruses do not meet these characteristics of living things: • Cannot reproduce on their own - must infect host cell to reproduce • lack enzymes for metabolism – must infect host cell to carry out metabolism • don’t grow

  17. Virus Shape and Structure • Viruses have 2 component parts: 1. Nucleic acid core - (DNA or RNA) 2. Capsid (protein coat) surrounds Nucleic acid core– gives the virus its distinct shape Examples:

  18. 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.

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

  20. Type of Viral Infections • Lytic Cycle: the virus destroys the host cell by causing it to lyse (burst) • Examples of Lytic Viruses: • Adenovirus (cold virus) • Meningitis • Polio

  21. Bacteriophage protein coat Bacteriophage DNA Bacterial chromosome Bacteriophage attaches to bacterium’s cell wall Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells. Bacteriophage injects DNA into bacterium Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage Bacteriophage DNA Bacteriophage protein Bacteriophage takes over bacterium’s metabolism, causing synthesis of new bacteriophage proteins and nucleic acids

  22. Lysogenic Viruses attack the host cell, but do not immediately kill it • Viral DNA/RNA (prophage) is inserted into the host cell’s DNA/RNA • Host cell continues normal functioning, but will replicate the prophage every time it divides • This cycle may continue for years, but can go in to the lytic cycle at any time • Examples • Herpes Simplex I and II • Human Immunodeficiency Virus (HIV)

  23. Bacterial chromosome Bacteriophage DNA Bacteriophage injects DNA into bacterium Bacteriophage DNA (prophage) can exit the bacterial chromosome Lytic Cycle Lysogenic Cycle Bacteriophage DNA (prophage) may replicate with bacterium for many generations Bacteriophage DNA forms a circle Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells Prophage Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage DNA inserts itself into bacterial chromosome

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