Difference between VIRUS and BACTERIA - Find out!

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Did you know that the existence of viruses and bacteria on Earth predates the appearance and evolution of the vast majority of living beings today? Both are invisible to the human eye, and are known worldwide for the various diseases they cause, both in humans and in other living organisms.

However, the terms "virus" and "bacteria", in some areas, are commonly used interchangeably and, therefore, erroneously, since there are numerous differences between the two. In addition, symptoms of infection to differentiate between viruses and bacteria They are also different, as well as the type of medication to be used to combat them. Continue reading this interesting post by Green Ecologist and you will discover in detail what is the difference between virus and bacteria.

Difference between viruses and bacteria - summary

Starting from the main difference between virus and bacteria, for which the latter are considered as living beings and, on the other hand, the former are not, there are more differences that we will see in detail in the following list:


Bacteria are much bigger than viruses (sometimes up to 100 times bigger), being possible the observation of these by means of optical microscopy, whereas to see the virus it is necessary electron microscopy of greater resolution.


The anatomy of bacteria includes a resistant cellular wall, as well as structural membranes and different intracellular organs (ribosomes, cytoplasm, bacterial genome, among others). Viruses, on the other hand, only have their genetic material included within the so-called viral capsid.


In bacteria the reproduction process is complex and is characterized by the ability of the stem cell to reproduce autonomously, that is, without the need for another organism to be able to divide and transmit its genetic information to its daughter cells, which are also capable of dividing again and continue with the reproductive process. However, viruses are unable to reproduce without a living being to infect or parasitize, that is, without the help of the enzymatic and reproductive machinery of another cell that they infect, thus allowing their reproduction through a process of replication of the genetic material that creates the "new" virus.

Difference in the spread of viruses and bacteria

When bacteria infect an organism, the effects of their contagion are due to the action of different metabolic products of the same, which are harmful to the infected organism, thus causing various diseases for which the supply of antibiotics that remove the cell wall of bacteria and, therefore, cause bacterial death.

On the contrary, when faced with a viral infection, the cells of the infected organism will be directly attacked, since the virus clears and breaks healthy cells directly to guarantee their survival, causing serious imbalances in cell organization and, in the case of animals, in their immune system. To cope with a viral infection, you will need vaccination application that end the life of viruses, or virostatic action drugs that stop the multiplication of the virus inside the body, as well as other medications that reduce the effects of the infection, such as fever.

Both can be spread in various ways: direct contact between people, some from animals to people or vice versa, having contact with contaminated surfaces or with contaminated materials and fluids (feces, urine, mucus, saliva or blood), by contaminated food, etc. The contagion itself or the route of transmission will depend on the type of virus or bacteria of which it is spoken.

What is a virus - definition and characteristics

Viruses are molecular and protein aggregates lacking a life of their own. However, they do have genetic elements, and they constitute one of the most numerous and diverse groups of systems or organisms that have evolved on planet Earth. Between the main characteristics of viruses stand out:

  • They need to infect other organisms to survive, being able to attack the cells of animals, plants, fungi, bacteria and other microorganisms; even other viruses.
  • They do not perform any type of vital function, other than replicating to maintain the infection in the host organism, with the aim of colonizing it and expanding the presence of new viral structures, always identical to the original virus.
  • There are different types of viruses, depending on their structure and type of genetic material.

Learn much more about them in this other Green Ecologist article on Are viruses living beings or not?

What is a bacterium - definition and characteristics

Now that you know the difference between virus and bacteria and more characteristics on the first, we can clarify what are bacteria. Bacteria are a group of single-celled microorganisms really extensive and varied. They are capable of surviving in very hostile environments on the planet, both in aerobic and anaerobic conditions, as well as in areas of high or low temperatures. They thus have a great survival resistance, which is directly related to many of the main characteristics of bacteria:

  • They are made up of prokaryotic cells, lacking a cell nucleus, but with various intracellular organelles, such as ribosomes and cytoplasm, as well as a resistant cell wall and structures associated with communication with other bacteria and the environment in which they inhabit. They are capable of living like this, both in isolation and in association (beneficial or harmful) with other organisms.
  • They reproduce by cell division, the genetic material of the daughter cells being identical to that of the mother cell, except in certain exceptions in which the exchange of genetic material between bacteria occurs.
  • There are a great variety of families of bacteria, which are grouped according to their structure and functionality.

Discover much more about them and other similar organisms in this other Green Ecologist post about the Monera Kingdom: what it is, characteristics, classification and examples.

If you want to read more articles similar to Difference between virus and bacteria, we recommend that you enter our Biology category.

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  • Delgado, M. I. & Hernández, J. L. (2015) Viruses, are they living organisms? Discussion in the training of Biology teachers. Enrique José Varona Pedagogical University, Havana, Cuba. Volume 61, pp. 1-7.
  • Sierra, J.J. (2004) Taxonomy and human immunodeficiency virus. Mexican Journal of Clinical Pathology, Redigraphic. Volume 61 (1).
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