Viruses

But first…Classification Recap

And now back to Viruses!

2.2

Living vs. Non-Living?

• Organization (Cells)• Metabolism

• Responsiveness• Growth

• Reproduction• Evolution• Ecology

Examples of Viral Diseases

• common cold, chicken pox, AIDS, cholera, rabies, influenza, hepatitis B, cold sores, measles, mumps, pneumonia, etc.

• hepatitis C & links to liver cancer• many animal & plant viruses

Epidemic vs. Pandemic

• limited vs. widespread (usually global) geographic region

• Have you seen this film?• http://www.youtube.com/watch?v=4sYS

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Host Range

• most are very specific

• some can infect many species

• bacteriophage infects bacteria cells

Basic Structure

• protein capsid• genetic material

(DNA or RNA)

Classification

Viral Reproduction• lytic cycle (lysis)• lysogeny (dormancy)

Vaccinations

• global elimination of smallpox by WHO in 1980

• human papillomavirus (HPV) & connection to cervical cancer

Gene Therapy

Viroids

• small infectious pieces of RNA without capsid

• discovered in 1971• responsible for

some plant diseases

Prions

• abnormally-shaped infectious proteins

• cause rare diseases in mammals

• consumption of infected animals causes prions to enter blood and travel to brain