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
• What do we know about viruses?
• Why are viruses not classified in any of the
6 kingdoms?
VIRUSES
Organic?
BACTERIOPHAGE
RABIES
FLU
EBOLA
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
• OLD ways of thinking
– viruses Contain 2 of 4 organic compounds
– Proteins and nucleic acids
New: 4 of 4 organic compounds
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
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
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
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
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
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