• Project STEMinist

Are Viruses Alive?

Although viruses have some features of a living organism, they are not alive. First, all living things must have metabolism and process energy for chemical reactions. ​The energy one uses to run and jump comes from independently breaking big food molecules into smaller pieces that can be used or stored in their cells. Viruses are too small and simple to collect or use their own energy. All the energy that goes into the construction of new viral genetic information comes from the host cell that a virus takes over. Even though viruses definitely benefit from the use of energy, they are merely latching onto the host’s metabolism to get the energy they need. Similar to how a parasite receives its food, a virus steals the energy of a cell and can not independently manipulate energy to replicate.

Some scientists consider viruses to be complex because they can have an intricate asymmetrical shape with additional protein walls. However, complexity is not only defined by exterior shape. A cell must have structures to help it function, such as the nucleus and mitochondria in animal cells. A virus may have a complex shape, but it is essentially a gift-wrapped nucleic acid. A virus does not have any complex interior structures or complicated independent processes that occur within its shell.

Even though viruses have a barrier to the outside and are protected by a capsid protein shell, they cannot maintain homeostasis. One of the main goals of having a barrier to the outside is to be able to create a stable internal environment. However, the barrier for a virus does not do this. A virus has no way to control its internal environment and cannot maintain homeostasis.

Another crucial point is that viruses are not capable of independent replication. They have to replicate within a host cell and are dependent on their host to provide many of the requirements for their replication. Some organisms, such as ​Chlamydia​ spp., have not yet been grown outside a cell, but they carry their own transcriptional machinery and fall into the evolutionary kingdom of Bacteria. Unlike the Chlamydia​ spp. Bacteria, a virus does not have its own structures to independently replicate and reproduce once inside a cell. Throughout a virus's life, it can only dependently multiply and does not grow larger. This lack of growth is another example of how a virus cannot be living.

Sense is defined by an almost immediate reaction to some change in the environment and is another important trait of living organisms. A virus can not change its behavior in response to touch or sound like humans, bacteria, or sea sponges might, and there has not been enough research done to definitively say that viruses do respond to stimuli.

Lastly, the most convincing argument of some scientists has to do with evolution and a virus’s ability to contain genetic information. Viruses can replicate genetic information, but they require a host cell to do this. Because viruses are constantly using the cell to replicate, mutations are bound to form. If it was not for the host cell that the virus relies on to replicate, viruses could not evolve because their genetic information would not be replicating and mutating. Viruses do contain genetic information, such as DNA or RNA. However, they do not have other structures that can utilize and process the genetic material independently. If a virus is alive, should we not also consider a single DNA molecule to be alive? For example, a plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate. Similar to a virus, they can hold a DNA molecule and replicate inside of a host cell. If these plasmids are not considered living, a virus should not be either. All in all, viruses should not be considered living because they do not meet all the required criteria to be classified as alive. BY: Kenedy Quandt

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