Viruses

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Viruses

• Are they alive?

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Figure 18.1 Comparing the size of a virus, a
bacterium, and a eukaryotic cell
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Virus Structure

• Protein Coat
• DNA or RNA
• Enzyme

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Figure 18.2 Viral structure
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What viruses cannot do

• No metabolism
• Cannot reproduce on their own
• Cannot move
• No respiration
• Do not eat
• No cellular structures

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Figure 18.3 A simplified viral reproductive cycle
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Mode of Attack

• DNA to mRNA to Ribosomes to make new viruses
• RNA to Ribosomes to make new viruses
• Result the cell dies

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Figure 18.4 The lytic cycle of phage T4
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Figure 18.02x1 Adenovirus
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Figure 18.02x2 Phages
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Pathways

• Lytic RNA or DNA routes
• Lysogenic RNA to DNA to mRNA to Ribosomes A
  reverse route through the cell.

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Figure 18.5 The lysogenic and lytic reproductive
cycles of phage ?, a temperate phage
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Table 18.1 Classes of Animal Viruses, Grouped by
Type of Nucleic Acid
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Ebola and Hantavirus
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Edward Jenner

• Created the first immunization against smallpox
  about 200 years ago.
• The dead virus spurs the immune system to
  prepare for the real virus ahead of time.

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Figure 18.6 The reproductive cycle of an
enveloped virus
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Human Immunodeficiency Virus (HIV)
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The HIV Virus
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HIV

• History of the virus
• Other types (FELV), (SIV) and (HTLV)
• Where did it come from?
• Immunizations?
• Cure?
• HIV I and HIV II