Transcript Viruses

Viruses
Are they living things?!?
Review
• Which correctly identifies the organization of
living things from least complex to most
complex?
• A. Community, Organism, Cell, Atom
• B. Tissue, Ecosystem, Cell, Organ System
• C. Molecule, Tissue, Population, Community
• D. Atom, Organ, Community, Population
Review
• What 8 characteristics
define living things?
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What do viruses look like?
• All Viruses
– Capsid
– DNA or RNA
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• Some viruses
– Envelop
Comparison with a bacteria
• Bacteria
– Made up of cells
– Get energy
(metabolize)
– Respond to stimuli
– Reproduce asexually
– Evolve
• Virus
– Not a cell--no cell
membrane, ribosomes
– No metabolism
– ?Response to stimuli?
– Reproduce using the
cells machinery as a
host
– Evolve
Bacteria vs. Viruses
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• Bacteria can be treated with antibiotics that destroy the
cell’s wall.
– Ex. Penicillin to get rid of Strep throat!
• Would antibiotics work on a sore throat caused by the
common cold virus?
Virus Reproduction
• Lytic: Uses cell and destroys cell.
• Lysogenic: Uses cell and hangs out inside until
the right time to strike!
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Chicken Pox
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• Varicella virus
• Lytic cycle--pox
• Lysogenic cycle--can
remain dormant and
come back as shingles.
• What does the vaccine
do?
Vaccines
• Trick your immune
system into producing
a response to an
antigen and make
antibodies.
• Can be for a virus or
bacteria.
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What do antibodies do?
• Antibodies make it
easier for your body’s
immune system to
recognize and destroy
pathogens before you
get “sick”
• “Memory”
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Why vaccinate? Why not just
treat the symptoms?
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• If there is no host, the
virus may no longer be
able to exist.
• Smallpox was
eradicated in 1977
through a world-wide
vaccination program.
Types of Vaccines
• Live, attenuated
– Chicken Pox
– MMR
– Polio “drink”
• Killed
– Flu
– Polio shot
• Component
– Hepatitis
• Toxins
– Tetanus
– DPT (whooping cough)
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“Tricky” Vaccines
• Influenza-– Why do we have to get
a new one every year?
– Why doesn’t it always
work?
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• HIV--Why don’t we
have one?
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Virus Question
• Peer edit:
– How many characteristics of life did they mention?
– How many characteristics of life did they relate to the
virus?
– How many characteristics of life did they explain using
example from a virus why the virus does or does not
display the characteristic?
– What could they add from what we talked about today
to support 1-2 characteristics of life?
What makes a good open response?