Difference Between Virus and Bacteria

There are different types of microbes in our surroundings and some of these microbes are useful to humans, whereas some of them cause various harmful diseases. Apart from this, bacteria and viruses cause the majority of diseases. They lie between mild to severe disease. Bacteria are tiny, single celled organisms that get their food from the environment and their surrounding. Some bacterias are good for the human body, for example Lactobacillus as they help in our digestive activities and keep harmful bacterias outside from the body. Whereas viruses are even more smaller than bacteria and they exist in both living and nonliving form. Outside the host body they are in nonliving form whereas when they are inside the host body they are a living organism and utilize the host cell process.

Virus versus Bacteria

                          Bacteria

                                Virus

1.Bacteria are totally living in nature.

1. Viruses are present in both living and nonliving form.

2. Cell wall of bacteria is made up of lipopolysaccharide or peptidoglycan. 

  2. Cell wall is absent but a capsid is present in them.

3. Size of bacteria is between 900-1000nm. 

3. Size of the virus is between    30-50nm.

4.They can survive without a host.

  4.They cannot survive without a host.

5. Bacteria reproduce mainly by binary fission.

    5. They reproduce by lytic fission and produce their similar copies.   

6. Ribosomes are present in bacteria.

    6. Ribosome is absent in bacteria.

7. RNA and DNA float freely inside cytoplasm.

    7. RNA and DNA are present inside the proteinous covering.

8. Antibiotics are effective for bacterial infections.

  8. Antivirals are effective for viral infection.

9. Bacteria causes disease like food poisoning, ulcers, pneumonia,etc. 

  9. Virus causes infection like AIDS, common cold, chickenpox, etc.  

10.Most of the bacteria can reproduce without a host.

  10. viruses need a host for their reproduction process.

11. bacterias are both pathogenic and parasitic in nature.

    11. They are only parasitic in nature.

12. Bacterial infections are generally localised.

    12. Viral infections are systemic.

13.Incubation period of bacterias is 1-2 weeks.

    13. Incubation period of the virus is 20 days-2 months.

14. Example of bacterias: Vibrio cholerae, Staphylococcus, etc.

    14. Example of Viruses:

 HIV, Rhinovirus,etc.

What is Bacteria?

Bacteria are microscopic single- celled organisms, they can live in soil, the ocean, inside the human gut. Humans have a very complex relationship with bacteria as they help them in various ways, such as by curdling milk into yogurt or helping with our digestion. 

Structure of Bacteria

Bacteria are single-celled organisms who lack nucleus, and contain DNA that either floats freely in twisted form or in thread-like structure known as nucleoid. In bacteria ribosomes are spherical units where proteins are assembled from individual amino acids using information encoded in ribosomal RNA.

Bacteria are covered by an outer cell wall and an inner cell membrane but certain bacteria do not have cell walls like mycoplasma and some bacteria may have a third layer also known as a capsule. Flagella is also present on the surface of bacteria.

Classification of Bacteria

Bacteria are classified on the basis of below features:

  1. Shape

  2. Composition of the cell wall

  3. Mode of respiration

  4. Mode of nutrition

  1. Classification based on shape:

  1. Bacillus (rod shaped)

  2. Spirilla or spirochete (Spiral)

  3. Spirilla or spirochete (Spiral)

  4. Vibrio (Comma-shaped)

     2.   On the Basis of Composition of Cell Wall:

                         A.Peptidoglycan cell wall: Gram positive bacteria

                         B. Lipopolysaccharide cell wall: Gram negative bacteria

    3. Bacteria on the Basis of Nutrition:

  1. Autotrophic bacteria

  2. Heterotrophic bacteria

           4.  On the Basis of Mode of Respiration:

                         A. Aerobic bacteria: Lipopolysaccharide cell wall

                         B. Anaerobic bacteria: Mycobacterium

    Properties of Bacteria

     Mainly there are three properties of bacteria they are:

  1. They are unicellular

  2. They lack membrane bound organelles

  3. Usually microscopic in size

Infection Caused Bacteria

An infection occurs when another organism enters our body and causes disease inside our body. The organisms that cause infections are very diverse and can include things like viruses, bacteria, fungi, and parasites.

Infection Caused by Bacterias are:

  1.  Sore throat

  2. Urinary tract infection(UTIs), caused by coliform bacteria

  3. Food poisoning

  4. Gonorrhea

  5. Syphilis

  6. Chlamydia

  7. Tuberculosis

  8. Whooping cough

  9. Lyme disease

    10. Meningitis

    11. Cholera

What is Virus

Viruses are microscopic parasitic organisms usually smaller than bacteria and having a tendency to reproduce inside the host cell only. They cause so many diseases and death all over the world. They are made up of core genetic material either DNA or RNA and surrounded by a protective coat called capsid which is made up of protein.

Structure of Virus

They are small intracellular parasites which contain either DNA or RNA surrounded by a protective protein coat known as capsid. For propagation viruses mainly depend on their host body. A complete virus particle known as virion. Main function of virion is to deliver its DNA or RNA to the host cell so that the genome can be translated or transcripted into the host body.

Classification of Virus

Viruses are classified on the basis of:

  1. Structure

  2. Shape

  3. Type of host

  1. On the Basis of Structure

  1. Cubical virus: they are also known to have icosahedral symmetry virus. Eg: Reovirus, Picornavirus

  2. Spiral virus: they are known as helical symmetry virus.

 Eg: Orthomyxovirus

  1. Radial symmetry virus: Eg: bacteriophage

  2. Complex virus: Eg: pox virus

   2. On the Basis of Shape

  1. Rabies virus: Bullet shaped

  2. Ebola virus: Filamentous shaped 

  3. Poxvirus: Brick shaped

   3. On the Basis of Host Body

Animal Virus: The viruses which infect and live inside the animal body including man are called animal viruses. Eg; influenza virus, rabies virus, mumps virus, poliovirus etc. Their genetic material is RNA or DNA.

  1. Plant Virus:  virus which lives inside the plant body is known as plant virus. Eg: The tobacco mosaic virus, potato virus, beet yellow virus and turnip yellow virus etc.

  2. Bacteriophage: It is a kind of virus which infect bacterial cells known as bacteriophage.

Infection Caused by Virus

  1. Influenza.

  2. Japanese encephalitis (inflammation of the brain)

  3. Measles, mumps, and rubella.

  4. Polio

  5. Rabies

FAQ (Frequently Asked Questions)

1. What is Virus and Bacteria?

Virus: Virus are microscopic parasites that lack capacity to thrive and they reproduce outside of the host. They are made up of core genetic material either DNA or RNA surrounded by a protective coat called capsid.

Bacteria: Bacteria are single-celled organisms who lack nucleus, and contain DNA that either floats freely in twisted form or in thread-like structure known as nucleoid. 

2. Difference between Bacteria and Virus in Points?

    Bacteria

Virus

1.Bacteria are totally living in nature.

1. Viruses are present in both living and nonliving form.

2.Cell wall of bacteria is made up of lipopolysaccharide ,peptidoglycan. 

2. Cell wall is absent but a capsid is present in them.

3. Size of bacteria is between 900-1000nm. 

3. Size of the virus is between    30-50nm.

4. They can survive without a host.

 4. They cannot survive without a host.