Hey guys thebestscienceblog12 here and today I will be talking about viruses. Viruses are the things that cause life threating diseases.
A virus is made up of a strand of DNA or RNA, surrounded by a protein coating called a capsid. Sometimes the capsid is surrounded by a fatty membrane used to protect it. The main purpose of a virus is to make you sick and infect you. They infect you by multiplying in you body.
For a virus to multiply it must first enter the body through wind, inhaling or touching your face. Once there it must get past you bodies defences including mucus in your nose. Once they get into your body they enter the blood stream and travel to find a host cell for it to multiply in( shown to the right). 
Once it finds a host cell it attaches itself to the cell and injects it with its own genetic information. When it gets inside the cell the virus's DNA or RNA uses the cells machinery to make copies of its self. When there are too many viruses in the cell the cell explodes and lets all the new viruses out.
Virus's can be either active or latent. When they are active it causes the host cell to make new viruses. This process destroys the host cell.
Latent viruses are viruses that enter a cell and makes its hereditary material become part of the cells hereditary material. It does not immediatly make new viruses. As the host cell reproduces the viral DNA is copied. After some time something like certain time and conditions can activate the virus. A cold sore on your lip is an example of a latent virus.
Three types of viral diseases are Smallpox, Warts, and the Flu.
Smallpox is a disease caused by the Variola major virus. Many scientists say that over the centuries it has caused more deaths than all other infectious diseases combined. Symptoms include high fever, backache, and fatigue.
Warts are growths on you skin caused by an infection with humanpapilloma virus or HIV. Common Warts usually appear on your fingers.
We wouldn't have the means to cure diseases like smallpox if it weren't for Edward Jenner. Edward was born in Berkeley, Gloucestershire on May 17, 174. He tested his famous experiment on an eight year old boy to prove that once you contract a disease you cant get the same disease again. His ideas were laughed at and considered ridiculous until he came back with undisputable proof that it was true. Edward came up with the first vaccine used to cure diseases.A vaccine is something used to combat viruses. Vaccines use weakened forms of the virus to help your body become immune to it.
Fun Facts
- The name virus comes from the Latin word meaning slimy liquid or poison.
- Walter Reed discovered the first human virus, yellow fever virus, in 1901.
- Viruses are not alive
Links
- For more fun facts on viruses
- For more on Edward Jenner
- For more about viral diseases
- Pic of Edward Jenner
- Pic of smallpox virus
- Pic of Warts virus
- Pic of Flu virus
- Virus entering cell gif
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