| From: Hobo Joe | 19/03/2001
11:07:54 |
| Subject: Viruses |
post id:
258476 |
| Hi! My name is Andrew, and I am a Uni student at UWS Hawkesbury. I was wondering if you could tell me what the current thoughts are on viruses. Are they animals or are they just strands of DNA? Cheers, Andrew | |
| From: Zardoz ® | 19/03/2001
11:14:05 |
| Subject: re: Viruses |
post id:
258483 |
| A virus is made up of two things,
a protective coat made of protein, and a strand of nucleic acid. This
nucleic acid is like a recipe, it allows the virus to make more viruses,
which in turn makes you sick. There are two different kinds of nucleic
acid, DNA and RNA. A virus can contain either DNA or RNA. In order to make new viruses the virus must copy its nucleic acid, it needs to copy the recipe, and put it in a protective coat, just like a winter coat protects you from bad weather. When DNA is copied the virus is very careful to make sure that it copies itself correctly. It has a built in spell checker to make sure it doesn't make any mistakes. Since it has a built in spell checker it changes very slowly, because it only rarely misses a mistake. Most viruses consist of four parts, the core, the capsid, the matrix, and the envelope. The core is located in the center of the virus and contains the virus' DNA or RNA wrapped together with some proteins. The capsid is made of protein and forms a shell around the core. The matrix forms a layer between the capsid and the envelope, while the envelope consists of lipids stolen from the cell membrane of the host cell that the virus is growing in. The envelope also contains proteins (mostly virus proteins). Viruses exist in just about every variation possible on this theme. Some viruses do not have a capsid for example, while others do not have an envelope. 
| |
| From: Wench of the Gods ® | 19/03/2001
11:22:17 |
| Subject: re: Viruses |
post id:
258491 |
|
As to whether or not they are alive or not... that is a tricky question. Viruses do not have the ability to metabolise things on there own - they cannot make their own energy, instead they use the energy made by the cell they infect. Most (but not all) carry all the genes they need to replicate their genome and package up the new viruses, which in many peoples minds makes them alive. However, technically, I would say they are NOT alive. Outside a host cell a virus is an inert cluster of macromolecules. It is only when they are placed within a cell that can supply them with an energy source and protein synthesis machinery, that they are able to do anything! Does that make sense??? | |
| From: Thermus aquaticus | 19/03/2001
11:22:58 |
| Subject: re: Viruses |
post id:
258492 |
| >>I was wondering if
you could tell me what the current thoughts are on viruses. Are they
animals or are they just strands of DNA? Thoughts on viruses? What exactly is it that you want? The whole field on virology summarized in 25 words or less? Viruses are not animals. By definition, an animal is an organism that belongs to the taxonomic kingdom Animalia. This does not include viruses. The other classical argument is whether viruses are alive. Some people argue yes on the basis that they evolve as such. But the majority opinion is no because the classical definition of life is the ability to derive energy. A cell is alive because it has an electron transport chain that can reduce substrates to derive ATP for energy. But a virus is merely nucleic acid in a protein shell (with some lipids and a few enzymes thrown in). A virus cannot derive its own energy. Outside of a living cell a virus is totally inert. | |