1. Chapter 18.2 Viruses Page 525

2. “Virus” Comes from the latin word “poison”

3. What is a virus? “particles of nucleic acid and protein that can only reproduce by infecting living things” blah, blah, blah Variety of sizes, shapes All enter living cells and use the machinery of the infected cell to produce more viruses. Will die after infected the cell

4. Kingdom? NO KINGDOM Because…. no characteristics of life! Therefore we can’t place it in a kingdom.

5. Structure DNA or RNA Protein Coat (Capsid)

6. Host Cell Every virus will use a specific cell to insert its DNA into. Ex – HIV? White blood cell White blood cell

7. Host cell Recognition Every virus has 3-D proteins called RECEPTOR SITES on it. They are the opposite of the proteins on its host cell.(puzzle) The two will lock together allowing the virus to inject its DNA/RNA.

8. Viruses are Specific Species Most viruses only like a certain species. Ex – cat and hiv Cell type Most only like certain types of cells. Ex- hiv only likes white blood cells.

9. Prophage When the virus’s DNA is integrated into the host cell’s DNA AKA –”provirus”

10. Reproductive Cycles: 1.Lysogenic 2.Lytic

11. Lysogenic Cycle When a virus injects it’s DNA into the host cell’s DNA. It will become part of the host’s DNA and replicate itself every time the host cell does too. Can hide for years. Can be retriggered anytime Ex – Cold sores (herpes virus)

12. Lytic Cycle On a search and destroy mission. Happens in cytoplasm! Produce new viruses immediately Kills the host cell.

13. Lytic vs. Lysogenic Cycles

14. Protection from Viruses? Vaccine! = prevention! “a weakened version of the real virus” Memory cells and immune system will act as if it is an active virus Next time the virus really enters, the body is ready! Your Immune System! White blood cells will eventually kill the viruses. Drink lots of fluids and get plenty of rest!

15. DNA vs. RNA DNA Viruses are relatively stable. Vaccines are made and these viruses are “stopped.” RNA is unstable and mutates easily. “Retroviruses” Therefore it’s changing constantly Vaccines can’t keep up with the changes.