Viruses

1
Viruses

• Living or Not???

2
Viruses

• Contain protein and nucleic acids.
• Do not eat, breathe or perform other biological
  functions.
• Can not live on its own, it can reproduce inside
  living organism that serves as its host.

3
Viruses

• Host organism that supports parasite. Viruses
  instruct hosts cell to produce viruses rather
  than healthy cells.

4
Classifying viruses

• Group by disease they cause
• Life cycle
• Type of genetic material they contain
• Basic shape
• Crystals polio virus
• Spheres influenza, HIV
• Cylinders tobacco mosaic virus
• Spacecraft attack bacteria

5
Lytic Cycle

• Virus finds host cell
• Enters cells or injects genes into cell
• Viruses genes take over host cell (virus factory)
• New viruses break out of host cell to find new
  host and repeat cycle

6
Lysogenic Cycle

• Virus enters host
• No viruses made immediately, but as the host cell
  divides, copies of the viruses genes passed on to
  each new cell.
• Remains inactive until change or stress