bellringer what is the difference between a bacteria and a virus? are bacteria and viruses harmful,...
TRANSCRIPT
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: ShapesShapes:
1. Bacilli-rods
2. Cocci- spheres
3. Spirilla- spiral, corkscrew
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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
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: ReproductionReproduction:
1. Binary fission-replicates, divides
2. Conjugation-bridge forms, genetic transfer; Diversity!
3. Endospore- enclose DNA, remain dormant until better conditions; forms spores
Endospore
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CONJUGATION
Bacteria Functions in Biosphere1. Decomposer (chemical
recycling)
2. Nitrogen Fixers
3. Bioremediation
4. Human uses for food
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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
• 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..
VirusesVirus- 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
22Some virus are pushed out by the cell, taking
some of the cell membrane with them.
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
VirusesRetroviruses- 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.
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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