Viruses Living or Non Living?

Viruses are infectious particles made of a shell of protein which contains either DNA or RNA. Millions can fit on the head of a pin or in a droplet of water and the largest can barely be seen with a microscope.

They are hundreds of times smaller than a cell and don’t have a nucleus or organelles like a cell. Adenoviruses – cause of the common cold.

Parts of a virus Capsid DNA or RNA

Some viruses have an Envelope- Attaches to part of the host cell membrane

Viruses attack host cells by attaching to their cell membrane and crawl inside. They can then do one of two life cycles.

Virus Life Cycles Lytic- virus infects cell and takes over the cell. The virus makes new viruses inside of the cell. Soon the cell is full of new viruses and will burst, spreading the disease

Lysogenic cycle-virus inserts its DNA into it’s host DNA and it hides there. Later it will pop out and begin the lytic cycle.

Viruses like HIV that causes AIDS, can hide for years in the nucleus of T-cells (white blood cells that help fight infection). People can have no symptoms, yet be spreading the disease to others.

Scientists have discovered that even pristine marine and freshwater environments harbor astonishing numbers of aquatic viruses. The viruses themselves appear incapable of infecting humans; however, they create a health threat by injecting disease-causing genes into common bacteria.

Certain Viruses are only found near sources of water such as Malaria Certain Viruses are only found near sources of water such as Malaria. Others have been traced to a specific body of water like the West Nile virus both of which are transmitted by mosquito.

Antibiotics won’t cure viral diseases! (The Doctor can’t cure your cold!) But they can be prevented by Vaccines which help your own immune system fight the disease.

Vaccines for smallpox, a deadly virus, helped wipe it out Vaccines for smallpox, a deadly virus, helped wipe it out. Other diseases that can be prevented by vaccines are: Measles Polio Mumps Influenza