1. VIRUSES A tiny, non-living parasite (particle) that enters and reproduces inside a living host cell. Two types: 1. Active 2. Hidden

2. Characteristics of Viruses Non-living Parasite Not a cell Cannot make or take in their own food Does not produce waste Multiply only in living cells

3. Shapes of Viruses Round (chicken pox, west nile) Tube/rod shaped (tobacco mosaic) Bullet (rabies) Robotlike (bacteriophage) Brick or thread like (Ebola)

4. Virus Size Smaller than cells Measured in nanometers (nm) Question: Which is larger Bacterium or Influenza Virus?

5. Naming Viruses For the diseases they cause For the organism they infect After the person who discovered them

6. Virus Structure Two basic parts Protein coating – protects the virus Inner core – genetic material Some may also contain a membrane envelope.

7. ACTIVITY: DRAW AND LABEL THE PARTS OF A VIRUS. ADD COLOR

8. How Active Viruses Multiply 1. Attaches to host cell 2. Virus genetic information enters host cell 3. Viruses takes over host cell functions (becomes a bacterium) 4. Virus proteins and genetic information reproduces 5. Host cell burst open releasing new virus Active viruses are always working and multiplying Examples: cold, flu

9. How Hidden Viruses Multiply 1. Attaches to host cell 2. Injects Virus genetic material 3. Virus genetics becomes the host’s cells genetics 4. Virus genetic material becomes active 5. Takes over cell functions 6. Host cell burst releasing virus Stays inactive for several years (hide & attack) When host cell divides so to does the virus genetics Example: Cold Sore

10. Viruses in Our Living World Viruses & Disease People: Cold – short lived – active AIDS - Hidden Plants: Animals: Rabies Distemper Usefulness of Viruses Gene Therapy – used to treat Cystic Fibrosis

11. Examples of Common Viruses Polio Chicken pox Smallpox Yellow fever Viral Meningitis West Nile Ebola Polio Chicken pox Small Pox Yellow Fever Viral Meningitis West Nile Ebola Yellow Fever

12. Summarize What is a Virus? Identifying basic structure and traits.