Education Journalist | Study Abroad Lead
Virus is an infectious agent that can only reproduce inside of its host organism. Viruses can infect a wide range of living things, including bacteria, plants, and animals. Given that it possesses traits of both the living and the non-living, it is viewed as existing on the edge of both. Viruses have very small structures and are so little that a microscope is required to see them. We have come to the conclusion that viruses are not alive; rather, they are dependent on host organisms for survival because they cannot exist for an extended period of time without them. They have been the primary cause of numerous epidemics of illness and fatalities throughout human history, viruses are mostly known for spreading diseases like Ebola, COVID-19 etc.
| Table of Content |
Key Terms: Virus, Replication, RNA, DNA, Host Cell, Living Organisms, Microorganisms, Gene, Non-Living Organisms
Are Viruses Living or Non-Living?
[Click Here for Sample Questions]
There have been unending speculations about whether viruses are living or non-living. Because viruses have traits of both living and non-living characteristics.
They have genetic material that has developed naturally through selection. They put themselves together.
- According to some scientists, viruses are neither living nor non-living because viruses have both living and non-living characteristics. That is, while a virus is within its host cell, it can replicate or reproduce just like a live organism. However, they lose this ability to reproduce when they leave the host cell, leaving them essentially as inert as a non-living substance.
- While some scientists think they are a form of pre-life that gives us an idea of how life evolved from self-assembling, self-replicating organic molecules, others think they are more akin to seeds that have the potential to become living things if they find the right environment, which is a host cell. Others still view them as straightforward parasites, stray gene fragments from a former host.
Viruses
Also Read:
Characteristics of a Virus
[Click Here for Sample Questions]
As viruses possess characteristics of both living and non-living organisms. The sections below can help one to differentiate a virus as a living or non-living:
Living Characteristics of Virus- Virus has the ability to reproduce or multiply inside a host cell.
- They have genetic material like DNA or RNA, proteins and enzymes for replication.
- They can mutate.
- They show irritability and are reactive to heat, chemicals and radiation.
- They can multiply and have the ability to transfer from one host to another.
- They are capable of causing viral diseases.
- Like pathogenic bacteria, a virus can also not live without living cells.
Read More: Virology
Non-Living Characteristics of Virus
- Virus cannot reproduce or multiply out of a host cell.
- They cannot have DNA and RNA together.
- They do not have cell organization, and protoplasm is absent.
- They can be crystallized and can be stored for a long period of time.
- They do not have cell organelles.
- Viruses are unable to metabolize.
- A virus cannot be killed by antibiotics.
- They do not respire or excrete.
Read More: Life Processes
Things to Remember
- A virus can be defined as a submicroscopic infectious agent that replicates only inside the living cells of an organism.
- Viruses are inert outside their host cell.
- They are non-cellular, which means they do not have cells. Most viruses possess a nucleic acid core made up of either DNA or RNAs.
- Viruses are considered to be neither living nor non-living as it possesses characteristics of both living and non-living.
- Although viruses are complex collections of components, including proteins, nucleic acids, lipids, and carbohydrates, they are powerless until they reach a living cell. In the absence of cells, viruses could not proliferate.
- Viruses can easily infect all life forms, from animals and plants to microorganisms.
Read More: Living and Non-Living Things
Previous Year Question
-
The concept of "Contagium vivum fluidum" was given by… [KCET 2021]
-
Banana bunchytop virus is transmitted through..........… [BITSAT 2011]
-
Which of the following statements is true about viruses? [KCET 2008]
-
T.O. Diener discovered a… [NEET 2009]
-
Virus are living, because : [NEET 2000]
-
Which of the following statements is correct ? [NEET 2019]
-
Rabies is caused by [DUET 2008]
Sample Questions
Ques. How can you say that virus is non-living? (3 Marks)
Ans. Viruses can replicate only inside a host cell as they depend on the host cell for reproduction. Without cells, viruses would not be capable to increase. That is the reason why a virus is generally considered non-living because it is living only inside the host cell. They do not have cell organization, enzymes, protoplasm is absent. They also cannot mutate out their host. So may also consider viruses as non-living.
Ques. Write a short note on the virus. (3 Marks)
Ans. A virus is an infectious microorganism made up of a protein-coated segment of nucleic acid (either DNA or RNA). Viruses can infect a wide range of living things, including bacteria, plants, and animals. Given that it possesses traits of both the living and the non-living, it is viewed as existing on the edge of both. Viruses have very small structures and are so little that a microscope is required to see them. They can cause viral diseases like flu, Ebola, Covid-19, HIV and AIDS, etc.
Ques. What are the characteristics of a virus as a living organism? (3 Marks)
Ans. The living characteristics of viruses are that they have genetic material like DNA or RNA, proteins and enzymes for replication. Inside its host, the virus can multiply or replicate. And they are also highly reactive to heat, chemicals and radiation, which shows that they are responsive. They also undergo mutation.
Ques. What is your opinion about considering viruses as living or non-living organisms? (5 Marks)
Ans. Both living and non-living properties can be found in viruses. They have genetic material that has evolved spontaneously through selection, therefore it fits into both categories. A virus can replicate or proliferate while it is inside its host cell, just like a living thing. When they depart the host cell, they lose this capacity for reproduction, becoming essentially inactive like a non-living object. Some believe they are more like seeds that have the potential to become living beings if they find the correct habitat, which is a host cell. While others think that virus is a sort of pre-life that provides us with an insight into how life emerged from self-assembling, self-replicating organic molecules. Thus one can conclude that the virus is neither living nor non-living.
Ques. Give a piece of evidence why viruses were considered alive. (3 Marks)
Ans. One evidence that supports viruses as being alive is that viruses follow Darwinian evolution. This theory is supported by the fact that viruses have gradually altered their DNA or RNA in order to overcome the immune responses of their host, helping them to sustain and replicate new viruses. This means they have essentially undergone Darwinian evolution.
Ques. Describe viruses from an anatomic perspective. (3 Marks)
Ans. If we describe a virus from an anatomic perspective, it can be classified as an essentially nucleic acid that is bound by a protective protein coat. The nucleic acid can either be DNA or RNA, however, it can not be both. In the case of DNA viruses, The DNA structure of a virus can either be single-stranded or double-stranded DNA in case of DNA viruses. Usually, RNA viruses have single-stranded RNA, and double-stranded RNA viruses are not that common.
Ques. What is the size of a virus? (3 Marks)
Ans. Viruses can range from less than 20nm to 500nm in their size. We know that viruses are too minute to be seen with naked eyes. HIV, a type of virus, has a diameter of about 120nm, which is 60 times smaller than an RBC, which is about 6,000-8,000nm in diameter. Also, the protein coat that surrounds the nucleic acid of the virus affects the shape of the virus. Study Guide Links:
Also Read:
Comments