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.
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.
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.
Bacteria are classified on the basis of below features:
Composition of the cell wall
Mode of respiration
Mode of nutrition
Classification based on shape:
Bacillus (rod shaped)
Spirilla or spirochete (Spiral)
Spirilla or spirochete (Spiral)
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:
4. On the Basis of Mode of Respiration:
A. Aerobic bacteria: Lipopolysaccharide cell wall
B. Anaerobic bacteria: Mycobacterium
Mainly there are three properties of bacteria they are:
They are unicellular
They lack membrane bound organelles
Usually microscopic in size
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:
Urinary tract infection(UTIs), caused by coliform bacteria
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.
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.
Viruses are classified on the basis of:
Type of host
On the Basis of Structure
Cubical virus: they are also known to have icosahedral symmetry virus. Eg: Reovirus, Picornavirus
Spiral virus: they are known as helical symmetry virus.
Radial symmetry virus: Eg: bacteriophage
Complex virus: Eg: pox virus
2. On the Basis of Shape
Rabies virus: Bullet shaped
Ebola virus: Filamentous shaped
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.
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.
Bacteriophage: It is a kind of virus which infect bacterial cells known as bacteriophage.
Japanese encephalitis (inflammation of the brain)
Measles, mumps, and rubella.
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?
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.