Are Viruses Living or Non-Living?

The Categorization of Viruses

The categorization of viruses as non-living or living organisms has been an issue of debate over 100 years within the scientific community. A virus is a tiny infective agent that has the capability of infecting all units of life forms including Archaea and Bacteria domains. They range from 20-400nm in length. Upon their discovery, scientists believed that they were poisonous and thus how their name got obtained. Nevertheless, researchers found that several diseases like rabies were caused by acellular organisms that acted like bacteria (Brown and Bhella 59). As a result, viruses got recognized as biological. This is because they were able to cause visible biological impacts on the victims they attacked. Therefore, they remained to be thought as the tiniest gene-bearing living organisms. However, upon further studies on their structure, scientists got divided on whether they are living or non-living organisms.

Not Alive

One of the crucial points that scientists hold to describe viruses as nonliving is that they are incapable of independent replication. Viruses have to replicate within host cells, and they usurp or use the cells’ tools for this (Koonin and Starokadomskyy 127). They lack the required metabolic processes needed for their replication and thus rely on the host cell. Notably, there exists a significant difference between viruses and other obligate intracellular parasites like bacteria. Viruses must utilize the host cell for their metabolic and replication machinery. Contrary, intracellular bacteria only utilize the host as an environment in which they can supplement their limited metabolic ability. Also, bacteria possess their replication machinery. In this case, they remain different from viruses and thus are non-living.

Also, viruses lack cells. They only contain a protein coat responsible for protecting their genetic material. This they lack cell membranes as well as other organelles such as mitochondria or ribosomes found in living cells. Further, other scientists consider them non-living as they do not use their energy. They only remain active at times when they are in contact with host cells. Notably, once on a host cell, they are capable of using the host cell’s tools and energy to replicate (Pradeu, Kostyrka and Dupré 59). Moreover, viruses only contain either RNA or DNA but not both. They also do not respond to external stimuli. Stimulus-response can get defined as the immediate reaction to a change in environment. Thus, viruses do not change behaviors in response to sound, touch or light like bacteria and humans.

Alive

On the other side, scientists who hold that viruses are living organisms maintain that they can adapt to their environment. Adaptation involves the capability of an organism to change for its survival in the environment. This feature remains critical to the evolution process and gets determined by external factors, an organism’s diet as well as heredity. Notably, viruses can live in two in two phases named the lytic phase and the lysogenic phase (Van Regenmortel 121). The lytic phase is when a virus actively replicates within a host cell. Consequently, the lysogenic phase is when the DNA of a virus gets incorporated in the host cell’s DNA and replicates at times when the cell multiplies. So, during the instances when the host has no adequate energy, the virus switches itself into the lysogenic phase. Notably, the virus reenters the lytic phase when the host conditions get back to normal conditions. This ability to adapt makes it a living organism. In fact, this characteristic makes it difficult for scientists to design an effective drug for HIV.

Also, viruses have RNA or DNA, which is the code for life. The possession of genetic material is a crucial characteristic towards the classification of being alive (Dupré and Guttinger 112). This is because DNA controls the evolution of an organism through its cells. Hence, just like other living organisms, viruses can evolve with time and thus able to adapt to the environment.

Opinion

From both sides of the argument, one can conclude that viruses are not living organisms. For instance, taking living organisms such as animals and plants, they possess cellular machinery that permits them to reproduce. However, viruses are only free forms of RNA or DNA that cannot replicate solely. They fully utilize the machinery of other cells to replicate. Also, viruses fail to fulfill the basic definitions of life that include the ability to grow, response to stimuli and metabolism (Brown and Bhella 60). They also lack self-sustaining and self-generated actions that remain evident in living organisms. Viruses remain inert until they come in to contact with living cells. Notably, without a host cell they cannot reproduce, and thus they are non-living.

Conclusion

The classification of viruses into either living or non-living organisms substantially depends on an individual’s interpretation of what is life. In fact, scientists should first agree on a single definition of life for them to settle on one side of the debate. However, extensive future research on the structure and functioning of viruses might assist in solving the categorization crises.

Works cited

Brown, Nigel, and David Bhella. “Are viruses alive?.” Microbiol. Today 43 (2016): 58-61.

Dupré, John, and Stephan Guttinger. ”Viruses as living processes.” Studies in History and      Philosophy of Science Part C: Studies in History and Philosophy of Biological and      Biomedical Sciences 59 (2016): 109-116.

Koonin, Eugene V., and Petro Starokadomskyy. ”Are viruses alive? The replicator paradigm         sheds decisive light on an old but misguided question.” Studies in History and Philosophy          of Science Part C: Studies in History and Philosophy of Biological and Biomedical     Sciences 59 (2016): 125-134.

Pradeu, Thomas, Gladys Kostyrka, and John Dupré. ”Understanding viruses: Philosophical  Investigations.” Studies in History and Philosophy of Science Part C: Studies in History       and Philosophy of Biological and Biomedical Sciences 59 (2016): 57-63.

Van Regenmortel, M. H. V. ”The metaphor that viruses are living is alive and well, but it is no more than a metaphor.” Studies in History and Philosophy of Science Part C: Studies in        History and Philosophy of Biological and Biomedical Sciences 59 (2016): 117-124.