Viruses and Bacteria Antibiotics work on Bacteria, NOT Viruses!
UNIT 8:Chapter 19 Bacteria and Viruses.
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Transcript of UNIT 8:Chapter 19 Bacteria and Viruses.
UNIT 8:Chapter 19 Bacteria and Viruses BACTERIA The beautiful
colors in this sulfur spring are caused by the bacteria that live
in it. Bacteria can survive in extreme habitats. Prokaryote Review
No nucleus Mostly single -celled
Circular chromosomes Cell walls Reproduce mostly asexually
Anaerobic or aerobic Heterotrophic or autotrophic 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. 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
Bacteria are Named by Shape
Coccus (ball-shaped) Streptococcus mutans Bacillus (rod-shaped)
Clostridium botulinum Spirilli (spiral-shaped) Treponema palladium
Prokaryotic Body Plan DNA capsule plasma membrane
ribosomes in cytoplasm bacterial flagellum Figure 21.3 Page 348
pilus cell wall cytoplasm Bacterial Shapes coccus bacillus
spirillum In-text figure Page 348 Prokaryotic Fission - 1 Bacterium
before bacterial chromosome
DNA replication bacterial chromosome DNA replication begins Figure
21.7 Page 350 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 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 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 Rhizobium Bacteria Good??
BACTERIA CAN HELP THOSE WHO ARE INSULIN DEFICIENT (SOME DIABETICS).
THIS IS DONE WHEN THE BACTERIAS DNA COMBINES WITH INSULIN PRODUCING
GENES FROM HUMAN. VIRUSES 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 bodys normal equilibrium (homeostasis). Figure 19-11 Viruses
and Cells
Section 19-2 Figure 19-10 Lytic and Lysogenic Infections 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 Lysis of
host cell is induced; infectious particles escape.
LyticPathway 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
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 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 LYTIC
CYCLE-virus replication Enveloped Virus (HIV) viral protein lipid
envelope (derived from host)
viral RNA reverse transcriptase Fig Page 356 viral coat (proteins)
Click the image to play the video segment.
Lytic and Lysogenic Cycles Click the image to play the video
segment. Video 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 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 Nature of Diseases
Contagious disease pathogens must directly contact a new host
Epidemic Pandemic (AIDS) Sporadic Endemic New Threats Emerging
Pathogens Drug-resistant strains Food poisoning
Ebola virus Monkeypox virus Drug-resistant strains Food poisoning
E. coli Salmonella