viruses a tiny, non-living parasite (particle) that enters and reproduces inside a living host cell....

VIRUSES

A tiny, non-living parasite (particle) that enters and reproduces inside a living host cell.

Two types: 1. Active2. Hidden

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

Shapes of Viruses

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

Virus Size

Smaller than cellsMeasured in nanometers (nm)

Question: Which is larger Bacterium or Influenza Virus?

Naming Viruses

For the diseases they cause For the organism they infect After the person who discovered them

Virus Structure

Two basic parts Protein coating – protects the virus Inner core – genetic material

Some may also contain a membrane envelope.

ACTIVITY:

DRAW AND LABEL THE PARTS OF A VIRUS.ADD COLOR

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

How Hidden Viruses Multiply

1. Attaches to host cell2. Injects Virus genetic material3. Virus genetics becomes the host’s cells genetics4. Virus genetic material becomes active5. Takes over cell functions6. 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

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

Examples of Common Viruses

Polio Chicken pox Smallpox Yellow fever Viral Meningitis West Nile Ebola

PolioPolio

Chicken poxChicken pox

Chicken pox

Small PoxSmall Pox

Yellow Fever

Viral MeningitisViral MeningitisWest NileWest Nile

Ebola

Yellow Fever

Summarize

What is a Virus? Identifying basic structure and traits.