VIRUSES

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VIRUSES

• B 4.C
• Compare the structures of viruses to cells,
  describe viral reproduction, and describe the
  role of diseases such as human immunodeficiency
  virus (HIV) and influenza

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Videos Viral invasion of the body
Part 1

• http//www.youtube.com/watch?vD2Uuc76DvlIfeature
  youtu.be
• http//www.youtube.com/watch?vsoIDiqxtTjMfeature
  youtu.be

Part 2
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What is a Virus?

• Much smaller than cells
• A NON-LIVING infectious agent made up of a core
  of DNA or RNA surrounded by a protein coat.
• Viruses need host cells to replicate the viral
  DNA. They enter a living host cell and hijack it
  to produce more viruses
• Viruses eventually kill their host cells

(Reproduce)
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Parts of a Virus

• Capsid Protein coat
• Genetic core DNA or RNA
• IS NOT LIVING!!!!!!!
• IS NOT A CELL!!!!!!!
• DOES NOT have organelles!!!!

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Protein Coat (part that hold the DNA)
Legs (anchor the virus to the cell)
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A cure for viruses?

• No said cure for a virus, only preventions
• Vaccine weakened or deadened form of a virus
• Viruses cannot be destroyed by antibiotics!!!!
• Antibiotics are for bacteria not viruses!

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We Classify Viruses by

• Shape (what they look like)
• Host (the type of cell they infect)
• Function (how they infect cells)
• Genetic Core (DNA or RNA)

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Viral Shapes
Shape
Helical
Enveloped
Binal
Examples
Tobacco Mosaic Virus
Influenza Virus
T4 Bacteriophage
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CAPSID
WEST NILE VIRUS
HERPES
SARS
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HEPATITIS B
BIRD FLU
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One Type of Viral Replication

1. Virus attaches to host cell
2. Virus injects DNA or RNA into cell
3. Viral DNA or RNA is replicated or
   reverse-transcribed
4. Transcription and Translation takes place to make
   capsid
5. Cell assembles viruses
6. Cell is lysed, new viruses are released and
   infect other cells

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Cell Virus
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Viruses that affect humans

• Influenza (the flu)
• HIV
• Chicken pox Shingles
• Herpes
• Common colds
• Epstein Barr
• HPV
• Rabies

• Measles
• Mumps
• Rubella
• Polio
• West Nile
• Hepatitis A, B, C
• Ebola
• Small pox

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Human Immunodeficiency Virus

• HIV causes AIDS
• HIV attacks Helper T-Cells, which are vital to
  our immune system
• Since HIV decreases the immune system, a person
  is more prone to secondary infections than a
  normal person

Mutates too quickly to make a vaccine
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InFLUenza

• Symptoms High fever, sore throat, fatigue,
  aches, coughs
• Mutates regularly. That is why we have vaccines
  yearly
• Can be air borne - When some one coughs or
  sneezes, you can contract the virus by breathing
  it in.

What shape are these viruses?
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SARS

• Severe acute respiratory syndrome
• Airborne- can be transmitted when an infected
  person coughs or sneezes.

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Common Colds

• Upper respiratory infections (nose, throat,
  lungs)
• Usually clear up in 2 weeks without complications
• More than 200 known viruses can cause colds

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Small pox

• Virtually eradicated!
• Only found in 2 labs on Earth Russia and US
• Small pox vaccine was made from cowpox
• Symptoms
• High fever, aches, rashes

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Human Papilloma Virus (HPV)

• Affects both men and women
• Sexually transmitted
• Can cause cervical cancer
• Gardasil vaccine that may prevent cervical
  cancer

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Herpesvirus

• Chicken Pox
• Fever
• Incubation of 14 days
• Red itchy rash
• Vaccination available
• Other herpesviruses include Herpes (cold sores
  and genital herpes)

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Measles

• High fever
• Sore throat, cough, sneezing
• Rash
• Dangerous for pregnant women
• You received a vaccine for MMR (measles, mumps,
  rubella)

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Polio

• Symptoms Fever, headache, muscle weakness,
  difficulty swallowing
• Hundreds of thousands affected until vaccination
  became available

Franklin D. Roosevelt, President from 1932 to
1945
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Ebola

• 1977 Ebola Zaire (picture)
• Named after the Ebola River in Zaire
• High hemorrhagic fever
• High death rate

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Viruses vs. Cells