Difference Between Virus and Mycoplasma

The main difference between virus and mycoplasma is that the virus is a non-living particle, which requires a host for its replication whereas mycoplasma is a true bacterium, which lacks a cell wall and, has an irregular shape. Furthermore, a virus is an obligate parasite while mycoplasma is mostly a free-living organism. 

Mycoplasma and virus are pathogenic microorganisms, which can cause diseases in animals, plants, and other organisms. 

Key Areas Covered 

1. What is Virus
     – Definition, Structure, Features
2. What is Mycoplasma
     – Definition, Structure, Features
3. What are the Similarities Between Virus and Mycoplasma
     – Outline of Common Features
4. What is the Difference Between Virus and Mycoplasma
     – Comparison of Key Differences

Key Terms 

Cell Wall, Genome, Microorganisms, Mycoplasma, True Bacteria, Viral Replication, Virus 

Difference Between Virus and Mycoplasma - Comparison Summary (1)

What is Virus  

A virus is a particle, which is non-living. Therefore, it does not show either replication or metabolism in the environment. Its genetic material can be either DNA or RNA covered by a protein core. The viral replication requires invading a host cell for both replication of the genetic material and synthesis of viral proteins. Viruses can infect all life forms including animals, plants, bacteria, and archaea. 

Difference Between Virus and Mycoplasma

Figure 1: Virus Particles

There are four types of viruses based on the shape: helical, icosahedral, prolate and envelope.  

What is Mycoplasma 

Mycoplasma is a true bacterium that is Gram-positive and anaerobic. It belongs to the phylum Firmicutes. Though it is a bacterium, it lacks a cell wall. Hence, it is pleomorphic, which means that it has an irregular shape. Also, mycoplasma cells can be lysed due to osmolarity changes in the culture medium. Therefore, it should be grown in an isotonic medium. Another characteristic feature of mycoplasma is the presence of a small genome when compared to other bacteria. Mycoplasma contains the smallest genome among all prokaryotes.  

Difference Between Virus and Mycoplasma

Figure 2: M. haemofelis

Mycoplasma can be either saprotrophic or parasitic. Due to the lack of a cell wall, it cannot be killed by antibiotics. Mycoplasma pneumoniae is an example of human-pathogenic mycoplasma, which causes atypical pneumonia.  

Similarities Between Virus and Mycoplasma 

  • Virus and Mycoplasma are pathogenic microorganisms. 
  • They do not have a cell wall. 
  • Both have small genomes. 

Difference Between Virus and Mycoplasma 


The virus refers to an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host while mycoplasma refers to any group of small typically parasitic bacteria that do not have cell walls and sometimes cause diseases. 


Virus is a non-living particle while mycoplasma is a living organism. Furthermore, mycoplasma is a type of true bacteria. 


Virus is an obligate parasite while mycoplasma lives freely in nature. 


The viruses are the most abundant biological entity while mycoplasma consists of the smallest genome among all prokaryotes.  


A virus can be 20-400 nm in size while mycoplasma is 0.1-1 μm in size.  


A virus has a rigid shape while mycoplasma has polymorphic or pleomorphic shape. 

DNA and RNA 

The virus may have either DNA or RNA while mycoplasma has both DNA and RNA. 

Metabolic Activity 

A virus has no metabolic activity while mycoplasma has a metabolic activity. 

Protein Synthesis 

Viral proteins are synthesized by the host’s cellular mechanisms while mycoplasma synthesizes its own proteins. 


HIV, Hepatitis A virus, and Rhino Virus are some viruses while M. pneumoniae, M. hominisM. genitalium are some of the mycoplasma. 


Virus is a non-living organism, which has to invade a host for its replication. On the other hand, mycoplasma is a small form of bacteria with a small genome. A virus consists of genetic material covered by a protein core while mycoplasma lacks a cell wall. The main difference between virus and mycoplasma is the organization and structure. 


1. Lodish, Harvey. “Viruses: Structure, Function, and Uses.” Molecular Cell Biology, U.S. National Library of Medicine, 1 Jan. 1970, Available Here
2. Razin, Shmuel. “Mycoplasmas.” Medical Microbiology, U.S. National Library of Medicine, 1 Jan. 1996, Available Here

Image Courtesy: 

1. “virus-particles-or-virions-of-a-hantavirus-known-as-the-sin-nombre-virus” By Cynthia Goldsmith, Brian W.J. Mahy (Public domain) via PIXNIO
2. “M. haemofelis IP2011” By Nr387241 – Own work (CC BY-SA 3.0) via Commons Wikimedia

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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