Mr. Zarate
8/29/14
Period 7
Are Viruses Alive? For many years there have been numerous controversies over whether a virus should be classified as living or nonliving. It is believed that viruses are considered nonliving because they lack a substantial amount of qualities to be classified a form of life and they are incapable of carrying out all life processes. For example, some characteristics that would justify a virus being nonliving would be that they are acellular: they are not made up of cells nor do they contain any cells, they do not have the ability to reproduce independently, and finally they are dead or inactive without invading a host cell because a host cell is what gives a virus the ability to have obtain many more characteristics of having life. Viruses are known to be acellular nonliving particle because they do not grow through cell division; instead they use the machinery and metabolism of a host cell. Since they are acellular they are not made up of living cells like plants and animals are. Also a virus does not have a cell membrane as many living cells do. They can’t grow on their own or undergo division. A virus is so small that they can only be seen with an electron microscope. They consist of a protein coat, which contains either DNA or RNA, and are not made up of cells. Therefore, a virus is not alive in the form of independent living. A virus can’t reproduce on its own. It requires a living host cell to reproduce because without it viruses act as nonliving chemicals. All living things reproduce or make more of their own kind. Reproduction can occur sexually with two parents or one with both sex cells, or asexual with one parents without exchange of genetic material. A virus is capable of replicating asexually inside of a host cell but with out a host cell the virus is nonliving and unable to replicate. Researcher Stanley established that a virus is made of nucleic acids, DNA or RNA, which is enclosed in a protein coat.