BIODIVERSITY I BIOL 1051 What are Viruses

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BIODIVERSITY IBIOL 1051What are Viruses?

• Professor Marc C Lavoie
• mlavoie_at_uwichill.edu.bb

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What are Viruses?
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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1. Viruses are very small
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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2. Viruses are NOT cells.

• Obligate intracellular parasites
• Small- filterable through bacteriological filters
  
• Contain a single type of nucleic acid, either DNA
  or RNA
• Contain a protein coat (the capsid) consisting of
  individual protein units (capsomeres)
• May contain a host-derived lipid membrane (the
  envelope) through which may be inserted viral
  proteins (spikes or peplomeres)
• Multiply inside living cells by using the
  biosynthetic machinery of the host

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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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3. Size and shape of viruses
Icosahedral symmetry
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1.3 Size and shape of viruses
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3. Size and shape of viruses
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3. Size and shape of viruses
Helical symmetry
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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4. Viral structures
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4. Viral structures
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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5. Virus multiplication
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5. Virus multiplication
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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6. Virus diversity
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6. Virus diversity (Baltimore classification)
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What are Viruses?

• 1. Viruses are very very small
• 2. Viruses are NOT cells.
• 3. Size and shape of viruses
• 4. Viral structures
• 5. Virus multiplication
• 6. Virus diversity
• 7. Viroids and Prions

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7. Viroids

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7. Viroids
Potato Spindle Tuber Viroid

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7. Prions

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7. Prions
PrP C host-derived prion protein PrP SC
Infectious conformational isomer

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7. Prions

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7. Prions Reproduction theories

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What are Viruses?

• REFERENCE MADIGAN, MT, MARTINKO, JM, PARKER,
  J. Brock Biology of Microorganisms, 10th ed,
  2003, PRENTICE HALL, p.231-265.
• PURVES, WK, SADAVA, D, ORIANS, GH, HELLER, HC.
  Life, The Science of Biology, 6th ed, 2001,
  Sinauer Assiciates Inc., p. 239-244.
• Charles Weissmann, THE STATE OF THE PRION, NATURE
  REVIEWS,MICROBIOLOGY VOLUME 2 NOVEMBER 2004
  861-871

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Lecture 4 What are Viruses?

• WEB sites
• http//library.thinkquest.org/13373/intro/intro.ht
  m
• http//www.tulane.edu/dmsander/WWW/224/Classifica
  tion224.html
• http//www.bocklabs.wisc.edu/ed/genomes.gif
• http//www.tulane.edu/dmsander/WWW/224/Classifica
  tion224.html
• http//www.uct.ac.za/microbiology/tutorial/other_a
  utonomous_or_semi.htm
• http//www.uct.ac.za/microbiology/tutorial/other_a
  utonomous_or_semi.htm
• Russell Kightley Media