• Submitted By: merrin
  • Date Submitted: 11/11/2008 1:41 AM
  • Category: Science
  • Words: 845
  • Page: 4
  • Views: 427

Leong Man Long 07018693

Up to the present, to define whether virus is organism or not are one of the most difficult problems. Even scientists can not give an explicit answer about what they are. For the several decades, many scientists try to deny virus is organism. However, their endeavor is still progressing. On the other hand, some religions have also put forward some various perceptions for this issue. Naturally, to define whether virus is organism or not become a controversial problem.

As we know, cell is a basic element to form an organism. However, virus is an exceptional type. They are about 100 times smaller than bacteria, also smaller than cell. Until now, there are 50000 species viruses have been discovered. Most of the viruses consist of gene which made from DNA and RNA, and their genes are protected by a protein coat. It has no any biological activity such as respiration. Most important, virus can not reproduce by itself. Once attaching the other cell, it will inject the DNA into the cell and copy itself rapidly. As a result, it causes many diseases. Just take mad cow disease as an example. Prion is a virus which cause mad cow disease. Once the Prion is transmitted, the defective proteins invade the brain and copy themselves by occupy the other cells. By this process, Prion seems to be an organism since they are conscious to reproduce.

However, on the viewpoint of scientists, they suggest that every organism should have the following characteristics. 1. Reproduce. 2. Obtain and use energy. 3. Grow, develop, and die. 4. Respond to the environment. For the virus, first of all, although Prion can reproduce itself, it is quite different from the others. When Prion get touch with cells, the cell will become Prion. It is also very similar to chemical reaction. By definition, chemical reaction is those which the substance shows as it interacts with, or transforms into, other substances. That is the reason why most...

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