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

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

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

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

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

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

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

Cold Sore

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

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!!!

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

Thank goodness we live in America!

Cow pox

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)

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

BREAKING NEWS 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