What is a virus?

1. What is a virus? It is a strand of hereditary material surrounded by a protein coating.

2. Viruses • They lack a cell membrane • Don’t have a nucleus • Don’t have organelles • They have a variety of shapes • They are too small to be seen unless you use the electron microscope

3. How do they multiply • They make copies of themselves- good for them, but bad for you • They cannot make a copy of themselves without the help of a living cell • So…. Are viruses living? • Scientist still debate over this today

4. What a virus does • They enter the cell and can become • Latent or inactive for awhile • Be active

5. Active Virus • It tricks the host cell into making new viruses • This actually destroys the host cell

6. Latent Virus • It’s hereditary material can become part of the cell’s hereditary material. • It does not immediately copy itself • It does not immediately destroy the cell • When the host cell reproduces it actually is copying the viral DNA instead • When certain conditions become just right it can activate the virus

7. Cold Sores • When a cold sore appears on your lip it is a latent virus becoming active in your body • While the virus is active it is destroying the normal cells in your lip • When the sore disappears it has became latent again • It is basically hiding in your body waiting for the time to become active again

8. Cold Sore

9. A virus cannot move by itself • It can be carried by wind • It can be spread through air after coughing or sneezing then inhaled by an animal WATCH

10. Bacteriophages • Viruses that infect bacteria • The differ from other viruses because they enter a bacteria and release their hereditary material • This whole cycle take ONLY 20 minutes then the affected cell releases an average of 100 viruses!!!

11. Vaccines • We use vaccines to prevent diseases • A vaccine is made from a weakened virus particle that cannot cause a disease anymore • Vaccines are the reason you have not had measles, mumps, small pox, chicken pox, polio or even rabies! • BE glad you are lucky enough to get vaccines- children die everyday from these disease because they don’t have a simple vaccine

12. Thank goodness we live in America!

13. Cow pox

14. The first vaccine • Developed by Edward Jenner • In 1796 • He developed a vaccine for small-pox • He noticed that people who got cowpox did not get smallpox • He prepared a vaccine from the sores of people with cowpox and injected it into healthy people to keep them from contracting smallpox (which kills)

15. antibiotics • Are not effective against viral disease • You body can only stop the virus by making interventions • Antiviral drugs are available for certain types of viruses • Mostly we avoid viruses by vaccinating people, & being sanitary

16. Helpful Uses?? • You might be wondering how a nasty virus could help someone • Gene Therapy- Scientist are experimenting with viruses to help people with genetic disorders and some are hopeful that this could be a cure for cancer someday BREAKING NEWS