Viruses as tiny bundle of genetic material

Added: 12/07/2005

Viruses are considered to be bundles of genetic material carried in the so-called `viral coat` (or capsid) made up of protein bits known as capsomeres. There are lots of different viruses which have various shapes, forms and functions. Some of them have an envelope (additional layer around the mentioned coat). But still each of them is just a microscopic parasite not seen with a naked eye.

Viruses are known as microscopic obligate intracellular parasites which are able to infect cells in living biological organisms. Viruses are the parasites which can reproduce by invading and controlling other cells. They lack a special cellary machinery for permanent self-reproduction.

Viruses are the tiniest and simplest of microbes. They are approximately ten thousand times smaller that any bacteria. As a rule, the term `virus` is referred to the particles infecting both single-celled and multi-celled organisms. Topically they carry a small amount of DNA or RNA but not both of them.

Viruses are surrounded by a special protective coat, which consists of proteins, glycoproteins, lipids or their combination. Their envelopes can be studded by a spike (made from proteins and carbohydrates) to help the partials of virus attach to host cells. Outside these cells viruses are known to be inert.

When viruses come in contact with host cells they begin to trigger the mentioned cells to engulf them. Or viruses may just fuse themselves into the cell membrane. In this way viruses are able to release their DNA into the host cell. Viruses give the host cells their own number of certain instructions (they override the normal functioning of the host cells). The mentioned actions shut down the host proteins production and directs the cell to produce the so-called `viral` proteins for making new virus particles.

Be aware that in spite of the fact the same virus can infect and reproduce in different kinds of animals, you may see different reactions in different hosts. For example, we know that flu virus is able to infect both animals, birds and people. According to virus study and applications there are several types of flu viruses which are not harmful to birds, but are able to kill people.
Speaking about viruses, it is important to pay attention to their origins. Unfortunately, they are not clear enough. There?s still no entire mechanism possible to be accounted for all kinds of viruses. As it is mentioned by scientific researches there are such viruses, which have only a few genes; they have probably originated from host organisms. The genetic material of such viruses has been derived from such transferable elements like transposons or plasmids. Viruses which have larger genomes usually represent extremely reduced microbes established symbiotic relationship with host organisms. This allowed the lost of the genes necessary for independent existence of a host.

Viruses are known to have played an important role in shaping the history of our planet and life. They shuffled and redistributed genes among organisms and caused diseases in plants and animals.

Viruses are considered to be the culprits of the majority of human diseases including ever present human cold, flu, AIDS, smallpox, definite types of cancer, etc. Viruses are able to infect virtually any types of cells: fungi, protozoa, bacteria, animals, plant and, no doubt, human. Viruses are considered to be true parasites. But virus is not the only microscopic parasite. Among other infectious parasites there are virusoids, prions and viroids. They are simpler in structure.

Rate this article:

Bad

Good

Article comments:

No comments for this article yet. Post your comment now!

Return to top of the page