Download Virus

Latin for
“poison”
A virus is a particle that can only be seen
with an electron microscope.
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Day 1 Goal:
The TAKS objective asks students to:
compare the structures and functions of
viruses to cells:
1. Compare & contrast structure of viruses and
cells
2. Overview of virus structure
3. Function of viruses
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Engage
Booooo, who cares about viruses?
Doing the following activity will help you understand:
– how quickly viruses spread
– why it’s important to prevent the spreading of
viruses
– THEN….you’ll want to know more about the these
tiny particles that can be so deadly!!!!
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Viruses spread!
If you were a
taxonomist,
how would you
classify these
infectious
particles?
Predict the
kingdom you
believe they
are assigned
to.
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Explore
Analyze the following virus. Using prior
knowledge of the structure of a cell, compare
and contrast cells to viruses.
.
ligands
.
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Explain
What is a Virus?
A virus is a non-cellular particle made up of
nucleic acid (genetic material) and protein that
can invade living cells.
• Cannot reproduce without a host
• Capsid head filled with DNA or RNA
• Covered in a sticky glycoprotein coat for
specific attachment to host cell site
Shapes of viruses
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Viruses are not cells and are not madeup of cells. They don’t…
 Contain a nucleus or cytoplasm
 Eat/ metabolize nutrients
 Grow and develop
 Carry on respiration
 Or perform other biological functions
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A virus is surrounded by a capsid (protein coat) which
determines the shape of the virus.
The capsid contains
nucleic acids (either DNA
or RNA).
Tail fibers
for attachment to
host cell.
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Viruses are classified by:
 type of host cell
 presence of DNA or RNA (retroviruses)
 shape:
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Now, try to assemble a basic virus:
• http://www.wisconline.com/objects/index_tj.asp?objID=MB
Y101
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Viruses differ from living cells in that all
viruses —
A metabolize nutrients
B can be destroyed by antibiotics
C have rigid cell walls
D must be reproduced in living cells
Remember, viruses can’t reproduce
on their own. The need to use the
machinery of a living cell to produce
their DNA and proteins.
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Day 2 Goal:
Describe the role of viruses in causing diseases
1. Diseases viruses may cause (just a few, there are too
many to cover and some still unknown)
2. How do viruses do this?
3. Treatment/ prevention
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Can you think of some illnesses
caused by viruses?
Viral Infections
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Flu (Influenza)
Common cold
AIDS
hepatitis
chicken pox
measles
mumps
E. Bola
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Pneumonia
West Nile
cervical cancer
Warts
Polio
Hepatitis
Rabies
Smallpox
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I still don’t get it! If a virus is not a living
thing than how do they replicate?
Flu Attack! How
A Virus
Invades Your
Body : NPR
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Wait, I’m made up of millions and millions of
cells. Does that mean ANY virus can infect
ANY type of cell?
How do viruses
recognize a target cell?
Activity
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Using the following illustration, explain
the process of VIRAL REPLICATION.
2.
1. Virus recognizes and
attaches to its host cell.
5.
3.
4.
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Viruses can
inject their DNA into a HOST cell,
taking over its machinery, reproducing, and then
killing the cell.
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Another example of a virus
reproducing
Virus attaches to
host cell.
Virus injects its
DNA
Cell lyses
(breaks apart)
and new viruses
are released
Virus DNA
commands host cell
to make new viral
parts
New viral parts
assembled
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Ex of a virus, its host cell and the disease
it causes:
Think
of a virus
virus and
the host
cellby
it attacking
targets.
The HIV
causes
AIDS
Predict
what would
this virus
if itthat
did
white blood
cells happen
called to
Helper
T cells
not have the host cell to attach to nor invade.
prevent infections in the body.
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VIRAL DISEASES
Disease
Transmission
Symptoms
AIDS/HIV
Sexual contact;
contaminated blood or
needles
Immune system failure; fatal
Common
Cold
Inhalation, direct
contact
Sinus congestion, muscle
aches, cough, fever
Smallpox
Inhalation
Blisters, lesions, fever,
blindness, scars; often fatal
Influenza
(Flu)
Inhalation
Headache, muscle ache, sore
throat, cough, fatigue, fever,
chills
Warts
Direct contact
Lumps on skin or mucus
membranes
Herpes
Direct contact
Open sores on mucus
membranes
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Should you ask for an
antibiotic when you have
the flu?
NO
Vaccines contain a weakened
or killed virus that provides
immunity to the disease.
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Can a disease be cured?
Virus
No!
Bacteria
Yes!
1. Vaccines can prevent
1. Antibiotics kill most
bacteria
2. Antibiotic resistance
them. A weakened or
dead strain of the virus
is injected
2. Antibodies form in 710 days and will give
immunity from the
virus.
occurs when some strong
bacteria aren’t killed by
antibiotics. They reproduce and
are resistant.
Natural Selection in action
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1. Most viruses infect a specific kind of cell. Which
of the following are infected by the human
immunodeficiency virus (HIV)?
A Helper T cells
B Liver cells
C skin cells
D Red blood cells
Remember, HIV infects helper-T
cells (white blood cells, not red)
causing the immune system to
be unable to fight infection
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2. Which of the following explains why
antibiotics can treat flu-like symptoms
caused by bacteria but are ineffective
against flu?
A Flu is a response to an antigen.
B Antibiotics require time to work.
C Antibiotics strengthen antibodies.
D Flu is caused by a virus.
Remember, the flu is caused by a
virus. They can sometimes be
prevented by vaccines, but cannot
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be cured with antibiotics.
Emerging
Infectious
Diseases
Stations
Activity
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