Transcript Bacteria and Viruses

Bellringer
• What is the difference between a bacteria
and a virus?
• Are bacteria and viruses harmful, helpful,
or neither?
• If so, how are they harmful, helpful, or
neither?
Bacteria and Viruses
Bacteria
• Prokaryotes-single
celled organism
lacking nucleus
Eukaryote,
remember?
Bacteria: Shapes
Shapes:
1. Bacilli-rods
2. Cocci- spheres
3. Spirilla- spiral,
corkscrew
Bacillus
bacteria
are rod or
sausage
shaped
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Coccus
bacteria
are
sphere
or
ball
shaped
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Spirillium bacteria have a corkscrew shape
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The tip of a
needle
The red and
yellow dots are
bacteria
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Metabolic Diversity
• Heterotrophs
– Must take in organic
molecules for energy
and supply or carbon
– Chemoheterotroph:
Most common.
– Photoheterotroph:
Least common
– Use photosynthesis for
energy but need to
take in organic
compounds for a
carbon source
• Autotrophs
– Make their own food.
– Chemoautotrophs:
make organic carbon
molecules but do not
require light as a
source of energy.
– Photoautotrophs:
make organic carbon
molecules and require
light as a source of
energy
Bacteria: Cell Walls
Cell walls:
• Bacteria with
peptidoglycan absorb
violet dye=gram positive
• Bacteria with less
peptidoglycan absorb red
dye=gram negative
Bacteria: Motility
Movement:
• Flagella allow reaction towards chemical or
physical signals
Bacteria: Reproduction
Reproduction:
1. Binary fission-replicates, divides
2. Conjugation-bridge forms, genetic transfer; Diversity!
3. Endospore- enclose DNA, remain dormant until better conditions;
forms spores
Endospore
CONJUGATION
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Bacteria Functions in Biosphere
1.
2.
3.
4.
Decomposer (chemical
recycling)
Nitrogen Fixers
Bioremediation
Human uses for food
Helicobacter
pylori
is the
pathogenic
bacteria
that can
causes ulcers
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Leprosy is a
bacterial
infection
that
decreases
blood flow to
the
extremities
resulting in
the
deterioration
of toes, ears,
the nose and
the fingers.
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LYME DISEASE
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TUBERCULOSIS
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STRUCTURE
•
•
•
•
•
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Nonliving
Composed of Nucleic acid and protein
Cause many diseases
Virology – Study of Viruses
Comparison of Viruses and Cells below
Char. Of Life
Virus
Cell
Growth
No
Yes
Homeostasis
No
Yes
Metabolism
No
Yes
Mutation
Yes
Yes
Nucleic acid
DNA or RNA
DNA
Reproduction
Only within host cell
Independently by
cell division
Structure
Nucleic acid core, protein
covering, some have
envelope
Cytoplasm, cell
membrane, etc..
Viruses
Virus- particles of nuclei
acid and protein
which reproduce by
infecting living things
DRAW and label
Tobacco Mosaic
Virus causes
tobacco plants to
develop a pattern
of spots
Some virus are pushed out by the cell, taking
some of the cell membrane with them.
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Viruses
• Lytic infection-virus enters cell, makes copies,
bursts out of cell
Viruses
• Lysogenic infection- virus embeds DNA into DNA
of host cell and replicated along with host cell’s
DNA
Viruses
Retroviruses- contain RNA as genetic
info; reverse transcription takes
place (HIV)
Viruses
Prions- contain no DNA
or RNA, only protien
(Mad Cow Disease)
Diseases Caused by Bacteria
and Viruses
• Bacteria produce disease
in one of 2 general ways.
Some damage the cells
and tissues of the
infected organism directly
by breaking down the
cells for food. Others
release toxins that travel
throughout the body
interfering with the normal
activity of the host.
Vaccine: preparation
of weakened or
killed pathogen.
• Antibiotics:
compounds that
block the growth
and reproduction of
bacteria
Viral Diseases
• Like bacteria,
viruses produce
disease by
disrupting the
body’s normal
equilibrium.
• Viroid; single stranded
RNA molecules that
have no surrounding
capsids.
• Prions: protein
infectious particles.
Viruses and Human Disease
• Control and Prevention of spread.
– Vaccination & Antiviral drugs
• Ex.) chickenpox vaccine, AZT, Acyclovir, protease
inhibitors.
• Emerging Viruses – exist in isolated
habitats
– Do not usually infect humans unless
environmental conditions favor contact.
• Several viruses are now linked to cancers
such as leukemia, liver cancer, Burkitt’s
lymphoma, cervical cancer.
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Which US President had polio?
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HERPESVIRUSES
BACK
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RHABDOVIRUSES
BACK
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RETROVIRUSES
BACK
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