1. UNIT 8:Chapter 19
Bacteria and Viruses

2. BACTERIA

3. The beautiful colors in this sulfur spring are caused by the bacteria that live in it. Bacteria can survive in extreme habitats.

4. Prokaryote Review No nucleus Mostly single -celled
Circular chromosomes
Cell walls
Reproduce mostly asexually
Anaerobic or aerobic
Heterotrophic or autotrophic

5. Archaebacteria Methane producers – anaerobic Halophiles Thermophiles
Halo = salt
Philia = love
Thermophiles
Thermo = heat
THESE BACTERIA CELLS HAVE
PEPTIDOGLYCAN IN THEIR CELL WALLS TO
PROTECT THEM FROM THE EXTREMELT HOT
TEMPERATURES.

6. Hey you, Bacteria, I love your shape!!! (Eubacteria)
Shapes: Cocci, Bacilli, and Spirilla
How are these words associated with bacteria?
Baking soda
Yogurt
Tooth decay
Vitamins
Road kill

7. Bacteria are Named by Shape
Coccus (ball-shaped)
Streptococcus mutans
Bacillus (rod-shaped)
Clostridium botulinum
Spirilli (spiral-shaped)
Treponema palladium

8. Prokaryotic Body Plan DNA capsule plasma membrane
ribosomes in cytoplasm
bacterial flagellum
Figure 21.3 Page 348
pilus
cell wall
cytoplasm

9. Bacterial Shapes
coccus
bacillus
spirillum
In-text figure Page 348

10. Prokaryotic Fission - 1 Bacterium before bacterial chromosome
DNA replication
bacterial chromosome
DNA replication
begins
Figure 21.7
Page 350

11. DNA replication completed Membrane growth moves DNA molecules apart
Prokaryotic Fission - 2
parent DNA molecule
DNA copy
DNA replication completed
Membrane growth moves DNA molecules apart
Figure 21.7
Page 350

12. New membrane and cell-wall material deposited Cytoplasm divided in two
Prokaryotic Fission - 3
New membrane and cell-wall material deposited
Cytoplasm divided in two
Figure 21.7
Page 350

13. Conjugation Transfer of plasmid Figure 21.8 Page 351 nicked plasmid
in donor cell
conjugation tube
to recipient cell
Conjugation
Transfer of plasmid
Figure 21.8 Page 351

14. Rhizobium

15. Bacteria Good??
BACTERIA CAN HELP THOSE WHO ARE INSULIN DEFICIENT (SOME DIABETICS). THIS IS DONE WHEN THE BACTERIA’S DNA COMBINES WITH INSULIN PRODUCING GENES FROM HUMAN.

16. VIRUSES

17. Are viruses alive? Only 1 characteristic of life: reproduction
Can only reproduce inside a host cell!
Process or reproduction = lytic cycle
Like bacteria, viruses produce disease by disrupting the body’s normal equilibrium (homeostasis).

18. Figure 19-11 Viruses and Cells
Section 19-2

19. Figure 19-10 Lytic and Lysogenic Infections

20. Diseases caused by viruses:
Common Diseases Caused by Viruses
Diseases caused by viruses:
Section 19-3
Type of Virus
Nucleic Acid
Disease
Oncogenic viruses
Retrovirus
Adenoviruses
Herpesviruses
Poxviruses
DNA
RNA
Cancer
Cancer, AIDS
Respiratory infections
Chickenpox
Smallpox

21. Lysis of host cell is induced; infectious particles escape.
Lytic Pathway
Tail fibers and other parts are added to coats.
Virus particles bind to wall of suitable host. Viral genetic material enters cell cytoplasm.
Viral protein molecules are assembled into coats; DNA is packaged inside.
Viral DNA directs host machinery to produce viral proteins and viral DNA.
Stepped Art Fig Page 358

22. Viral DNA usually becomes integrated into the bacterial chromosome.
Lysogenic Pathway
Viral DNA is excised from chromosome and cell enters lytic pathway.
Prior to prokaryotic fission, the chromosome and integrated viral DNA are replicated.
After binary fission, each daughter cell will have recombinant DNA.
Stepped Art Fig (2) Page 358

23. Viral Body Plans Genetic material is DNA or RNA Coat is protein
Complex virus
(bacteriophage)
Genetic material is DNA or RNA
Coat is protein
Helical virus
Polyhedral virus
Fig Page 356

24. LYTIC CYCLE-virus replication

25. Enveloped Virus (HIV) viral protein lipid envelope (derived from host)
viral RNA
reverse transcriptase
Fig Page 356
viral coat (proteins)

26. Click the image to play the video segment.
Lytic and Lysogenic Cycles
Click the image to play the video segment.
Video

27. Virus Nucleic Acid DNA viruses – stable, do not mutate rapidly
Single-stranded or double-stranded
Smallpox, Hepatitis B
RNA viruses – mutate rapidly, unstable
HIV, Rhinovirus

28. Evolution and Disease Host and pathogen are coevolving
If a pathogen kills too quickly, it might disappear along with the individual host
Most dangerous if pathogen
Is overwhelming in numbers
Is in a novel host
Is a mutant strain

29. Nature of Diseases
Contagious disease pathogens must directly contact a new host
Epidemic
Pandemic (AIDS)
Sporadic
Endemic

30. New Threats Emerging Pathogens Drug-resistant strains Food poisoning
Ebola virus
Monkeypox virus
Drug-resistant strains
Food poisoning
E. coli
Salmonella