What do the following have in
common?
Can you Identify the picture below?
Characteristics of Life
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Made of Cells
Reproduce
Metabolize (energy)
Grow
Respiration
Respond to environmental changes
• How can you prevent the spread of
disease? (3)
• How could know if an individual is infected
with a pathogen? explain
• What do we know about viruses?
• Why are viruses not classified in any of the
6 kingdoms?
– Have to have a host in order to reproduce
– Don’t have independent metabolism
– Don’t grow
– NOT CELLULAR
Virus Characteristics
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Do not use energy
Do not reproduce
Do not grow
Do not respond to environment
Are not cellular
• Obligate intracellular parasites
Why do some scientists consider
viruses to be “alive?”
• Contain all organic compounds
– Carbs, proteins, lipids and nucleic acids
– (same chemicals as a living organism)
• Under right conditions, being inside of a host cell,
they can carry out life process.
• They replicate (NOT reproduction)
Obligate intracellular parasites
• Commit inside a cell and uses the cell as a
host to function
VIRUSES
Organic?
BACTERIOPHAGE
RABIES
FLU
EBOLA
Virus Defined
• Infectious pathogen that infects living cells,
replicates inside cells making new viral
particles causing disease
• DNA encased in a protein/carbohydrate
coat
Types of Viruses
Polyhedral
helical
enveloped
Bacteriaphages attacking a
bacterial cell
Types of Viral Diseases
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Rabies
Ebola (hemorrhagic)
Flu (influenza)
HIV
Hepatitis
WE can only treat
symptoms of
viruses!!!
We can not CURE!!
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Chicken pox
Measles
Rubella
Mumps
Smallpox
Polio
Yellow fever
Parvovirus (canine)
Dengue fever
(hemorrhagic)
• Herpes
• How a Virus invades your cells
– http://www.youtube.com/watch?NR=1&v=Rpj0
emEGShQ&feature=fvwp
• Lysogenic:
http://www.youtube.com/watch?v=_J9xKitsd0
• http://biology.about.com/gi/o.htm?zi=1/XJ
&zTi=1&sdn=biology&cdn=education&tm=
2&gps=342_220_1020_583&f=00&tt=2&bt
=0&bts=1&st=14&zu=http%3A//student.cc
Virus Hunters
1. What factors influenced the spread of
disease?
2. What helped to prevent the spread of
disease.
3. Discuss one virus you learned from the
video and describe symptoms, treatment,
or interesting fact of the virus.
Vaccinations
• Stimulates Active immunity
• Injection of portion of virus (virus particles) that stimulate
an immune response….causes body to make antibodies
against particular diseases
http://health.howstuffworks.com/vaccine.htm
Immune
Responses
• Passive
– Formation of antibodies
– To the fetus thru the placenta, thru breastmilk, thru
administration of plasma (artificial)
• Active
– Formation of your own antibodies
– Vaccinations
– by contracting an infectious disease by exposure of
an antigen
1
2
4
3
• Lysogenic Infection:
• Similar to lytic infection however important
differences exist
• Instead of immediately replicating, viral DNA
incorporates itself into the host cell's DNA.
• Will remain dormant for significant amounts of
time.
• Give certain conditions (stress), the virus will
enter it's lytic phase similar to a normal lytic
infection
Prions
Proteinaceous infectious particles
What are they?
• Proteinaceous
infectious particles
– Infect brain or other
neural tissue
– Untreatable and fatal
– β sheets are thought to
lead to amyloid
aggregation.
http://learn.genetics.utah.edu/content/begin/dna/prions/
Bovine Spongiform
Encephalopathy
• Also known as "Mad
Cow Disease"
• Infected animals act
strangely and can be
aggressive
• Spread rapidly
through Britain by
rendering infected
animals into cattle
feed
Scrapie
• Recognized in sheep and goats for more than 250
years
• 1982  1st identified as a prion disease
Kuru
“laughing death”
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New Guinea
Muscle weakness, loss of
coordination, tremors,
inappropriate episodes of laughter
or crying
Was the most common death of
women
Mortuary feasting
– Forbidden by Australian
government in 1950’s
Viroid
• Single strand of RNA
(THAT’S IT!!)
• Infects plants
• 1 viroid disease has
killed over 10 million
coconut palms in the
Philippines