What is a virus?

13th January 2006 at 00:00
The word "virus" comes from Latin, meaning poison or slime.

From the relatively benign common cold and cold sore to the lethal diseases smallpox and Aids, the microscopic virus has a lot to answer for. These parasites only come to "life" once they have infected cells of plants, animals and bacteria, because only then can they reproduce through using their host.

Surrounded by a protein coat, they contain a core genetic code or viral genome of DeoxyriboNucleic Acidor (DNA) or RiboNucleic Acid (RNA), which is used to replicate the virus.

They can be passed through direct contact or by a carrier, such as an insect. Once inside the host cell the virus causes it to begin manufacturing the proteins necessary for virus reproduction. Then the virus is secreted out of the host cell to begin infecting other surrounding cells.

Because the virus uses the machinery of the host cell it is very difficult to kill, but the most effective approach is vaccination, where a weakened or dead virus is injected into a person to stimulate the production of antibodies, which can then kill off that type of virus.

The name H5N1 (pictured below as a coloured transmission electron micrograph) refers to haemagglutinin type 5 - the types of antigens (usually proteins) that are found on the surface of the virus, which bind it to the cell it infects - and neuraminidase type 1, which injects the viral genetic material into the infected cell.

Subscribe to get access to the content on this page.

If you are already a Tes/ Tes Scotland subscriber please log in with your username or email address to get full access to our back issues, CPD library and membership plus page.

Not a subscriber? Find out more about our subscription offers.
Subscribe now
Existing subscriber?
Enter subscription number

Comments

The guide by your side – ensuring you are always up to date with the latest in education.

Get Tes magazine online and delivered to your door. Stay up to date with the latest research, teacher innovation and insight, plus classroom tips and techniques with a Tes magazine subscription.
With a Tes magazine subscription you get exclusive access to our CPD library. Including our New Teachers’ special for NQTS, Ed Tech, How to Get a Job, Trip Planner, Ed Biz Special and all Tes back issues.

Subscribe now