We all have heard about the instrument called microscope
.It makes those organisms visible that are invisible to our naked eyes.Microorganism
- the word itself defines it.Micro
means very small and so microorganisms are those organisms that can only be seen through microscope.
Microorganisms are found more or less everywhere and so they are known to be the most abundant organism on our earth.They are also found inside the bodies of animal and human being.Most of them live alone whereas some of them live in colonies
i.e. they grow in groups. Fungi,algae,bacteria,protozoa
are the major groups in which the microorganisms can be categorized .1. Fungi
- They are the non-green plants because they lack chlorophyll and they depend rather they feed on decaying matters for their existence.Mould and Yeast are the two examples of this group.
etc which are a group of simple plants are the examples of this microorganism.
are the exception as their size is quite large and they can be seen by naked eyes.From this,we can say that all fungi and algae are not microscopic.3. Bacteria
- In our planet earth,bacteria are the oldest and the smallest organism found.They exist in four different forms or shapes.They are - curved,spherical,spiral
are the example of curved shaped bacteria.Cocci
is a spherical shaped bacteria,spirilla
is spiral shaped and bacilli
is an example of rod-shaped bacteria.
An amazing fact is that about 40 million bacteria are present in just a gram of soil.4. Protozoa
- Some of the common example of Protozoa are - Paramoecium,Amoeba,Euglena
etc.They are single-celled organism.
- The size of the viruses are much more smaller than the other microorganisms and so they can not be seen by any ordinary microscope.A very powerful microscope called Electron microscope
is used to see viruses.They reproduce inside the plants,animals or any bacterial cells but they can not be categorized as living or non living organism because they don't show any sign of life.
Some of the dangerous diseases like AIDS,Avian Flu,Swine Flu
etc. are caused by viruses HIV
(Human Immuno Deficiency Virus),H5N1
Microorganisms are useful to us in many ways.They have so many commercial uses
and environmental uses
.They are used in manufacturing of many medicines.They also have agricultural uses.
Microorganisms such as Lactobacillus acidophilus,Yeast,Streptococcus
etc. are very useful in the process of preparing curd,cheese and bread .A kneaded dough of flour,salt,sugar,Yeast cells and water is needed for the preparation of bread.Sugar present in the dough is converted to Alcohol and Carbon-dioxide by the microorganism Yeast.This dough is baked nearly at 180 degree centigrade,thus the Yeast cells are killed and the process of fermentation is stopped.The is how a porous and spongy bread is obtained.
In the formation of curd,the bacterium Lactobacillus
plays a very important role.Milk contains a protein called Casein
,which forms curd when coagulates and for this, the milk has to be acidic.Lactobacillus present in curd converts the lactose sugar to Lactic acid present in milk and that is why a spoonful of curd is added to lukewarm milk for the preparation of curd. Lactobacillus
are involved in the preparation of cheese and paneer.Rennet
is a substance which is found in the linings of the stomach of young cattle and is used by the manufacturers of dairy products to make the milk more acidic because Rennet helps in the formation of Lactic acid.
Alcoholic beverages are also prepared with the help of fungus such as Yeast by the process of fermentation.Fermentation is a process in which sugar,by the help of microorganisms is converted into an acid or Alcohol.Idli,Dosa,Dhokla are some of the Indian fermented food and are good for health. Xanthomonas campestris
, a bacteria which contains the Xanthum gum
is used in the manufacture of toothpaste.Shells of some algae such as Diatom is used in toothpaste for cleaning teeth.
Microbial diseases in plants and animals can be controlled by using antibiotics.Antibiotics
such as Penicillin,Streptomycin,Tetracycline
etc. are prepared from some bacteria and fungus.Penicillin is Penicillium
,a bacteria is used to obtain the antibiotics like streptomycin and tetracycline.
Some microorganisms are used to make vaccine that prevent the diseases such as Smallpox,Hepatitis,Polio,Cholera
etc. which are caused by microbes. Chlorella
is the example of such a microbe which is used as a food supplement because they are rich in proteins and other nutrients.
We have already read about the importance of Lactobacillus
in the preparation of curd but this bacteria is very helpful for human beings also.They help to digest food and destroy the disease causing microbes as they live in human intestine.
In the root nodules of some plants such as Pea and Soyabin,a bacteria called Rhizobium
is present that increases the fertility of the soil by a process called Nitrogen fixation.In this process the free atmospheric nitrogen changes into nitrogen compounds.Another example of this type of microbe is Blue green algae.
Some bacteria and fungi helps us by keeping our planet clean.These microbes convert the dead plants and animals into simple form which can be used by other plants and animals and by this way,the dead bodies are removed by the microbes.
We have discussed a lot about the useful microbes but there are so many harmful microorganisms also.The most harmful affects of microorganisms are that they cause so many diseases in human beings,animals and plants.They are also responsible for food spoilage. Pathogens
are the microorganisms that cause diseases i.e. they are the causative agents of diseases.Here are some of the communicable diseases
, i.e. the diseases that are transmitted from one person to another .1. Malaria
- The causative pathogen of this diseases is Protozoan and it is transmitted by the bite of female Anopheles mosquito.2. Typhoid
- Contaminated food is the mode of transmission of this diseases.Bacterium causes the diseases.3. Ringworm
- Caused by fungus and transmitted to other person by direct contact.4. Tuberculosis
- Air is the mode of transmission and causative pathogen is bacterium.Vaccination is needed for children in this disease .5. Cholera
- This disease is also caused by bacterium and is transmitted through contaminated food and water.6. Chickenpox
- It is a viral disease that means caused by a virus and transmitted by the physical contact wit the infected person and by air.7. Poliomyelitis
- The causative pathogen of this disease is also a virus and is transmitted through air and water.
There are some microorganisms that causes diseases in plants and animals.Some of the plant diseases are -1. Septoria leaf blotch
- It is caused by a fungus and is transmitted by air. 2. Apple scab
- This is also a fungal disease and the mode of transmission is air.3. Rust of wheat
- The causative pathogens of this disease is fungus and transmitted through air and seeds .4. Citrus canker
- It is a bacterial disease .
Some diseases in animals are - 1. Foot and mouth disease and Rinderpest
- Both these diseases are caused by virus and cattle are the affected animal by this disease. 2. Anthrax
- It is a bacterial disease in cattle . 3. Fin rot
- It is a disease in fish which is caused either by bacteria or fungus
Bread mould is a fungus that spoils the bread and there are so many other microorganisms that causes food poisoning
.Food poisoning may cause illness so we must be very much careful about the food we are taking.There are some factors such as - foul odour,surface discoloration,sour taste,slimy surface
etc. by which we can detect whether the food is in a good condition or not.
We must preserve our food carefully to avoid food poisoning.Boiling,dehydration,canning,using preservatives,pasteurization
are some of the methods by which we can preserve our food.