SL: Viruses Introduction Lesson

You Have a Virus!

Did you know that there are many more viruses out there infecting people, such as the Ebola virus? If you have ever seen the movie Outbreak, then you have a good idea about the devastation an Ebola outbreak can have on a country. You will learn more about this virus in a future discussion.

Meet the Viruses

Watch the presentation below to learn more. 

Viroids and Prions

• Viroids - consist of a single, tiny strand of RNA without a protein coat. Most are plant pathogens.
• Prions - prions are small sequences of misfolded proteins. They are the only type of pathogen that does not use DNA or RNA to cause disease. Prions attack animals, causing holes in brain tissue; Mad cow disease, or Bovine spongiform encephalopathy (BSE), is a prion-caused disease.

Viruses Challenge and Before You Go

Practice Time! Use the knowledge you learned from the lesson to complete the practice activities below.

Before You Go - You Need To Know

The following key points are from the explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

1. Are viruses living organisms?
   • No, they are not living because they are not made of cells and cannot reproduce without a host cell.
2. What are examples of viruses?
   • Flu, HIV, Herpes, Common Cold, Measles, Chicken Pox
3. What is the difference between the lytic and lysogenic cycle?
   • In the lytic cycle, the virus enters the host cell, makes copies of itself, lyses (breaks through the cell), and infects other cells. In the lysogenic cycle, the viral DNA or RNA becomes part of the cell’s DNA. The cell continues to reproduce, including viral DNA. It can remain dormant (weeks to years) before causing disease.

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