We generally consider the plant, animal and human species as the ecosystem. However, there are some other forms of life too, which form an integral part of the living world. These live forms are known as the microorganisms or microbes. Depending on the variant, they may or may not be visible to the naked eye. You must have seen the patchy green substance on an old bread slice. It is visible to us while the virus that spreads influenza (flu) is not visible. Both are microorganisms.

Microorganisms can be categorised into four major groups – bacteria, fungi, protozoa and algae. Some, like the fungus that grows on the bread, can be seen with or without a magnifying glass, while other varieties cannot be seen without a microscope. Microbes can be both good and bad for the living beings. 

Microorganisms: Where Do They live?

Microbes live around the world either independently or as parasites. They can be single-celled like the bacteria, some like algae and protozoa, or multicellular like the fungi. Microorganisms are found in all types of geographic and atmospheric conditions like the hot springs, ice cold climate, deserts and the marshy lands. Microbes are also found inside the bodies of animals and humans. Some microbes grow on other organisms and are parasitic in nature.

Microbes: Our Friends

The microbial world plays a dual role in our lives. One that we utilise and live with in our everyday lives and the other that is harmful for us and spread diseases. Let us learn more about them in detail.

Microbes in the Commercial World

Microorganisms are used in the large scale production of alcohol, wine and acetic acid i.e. vinegar. Yeast is also used for the production of alcohol and wine at a commercial scale. Yeast is grown on natural sugars present in grains like barley, wheat, rice, crushed fruit juices, etc. and fermented to turn them into alcoholic beverages.

Microbes and Their Medicinal Use

When we fall ill and visit a doctor, they may prescribe some tablets, syrups, injections or capsules to treat our ailment. All these types of medicines are made by microbes. We know how the microorganisms kill or replace other microbes. Thus the medicines for a certain physical problem is made using such microbes that can kill or curtail the growth of the microorganisms that cause the illness.

These medicines are known as antibiotics. With the advancement in science and technology, many treatments are being designed and produced based on bacteria and fungi. The antibiotics are produced by artificially growing certain microbes to cure a variety of ailments. These medicines are also mixed with the livestock and poultry feed to prevent microbial infection in animals, and are also used to control plant diseases. 

Microorganisms Help Increase Soil Fertility

There are certain bacteria which can turn the nitrogen from our atmosphere and use it to enrich the soil with nitrogen. This in turn increases the soil fertility. These microorganisms are commonly known as biological nitrogen fixers.

Microbes and the Nitrogen Fixation Cycle

Our atmosphere consists of 78% nitrogen in its gaseous state. Nitrogen is one of the most essential factors for the survival of all living being as a part of chlorophyll, proteins, nucleic acids and vitamins present within. The plants and animal cannot directly consume the nitrogen from the atmosphere. Some bacteria and the blue green algae in the soil absorb the nitrogen from the atmosphere and turn it into compounds of nitrogen. Once the nitrogen is converted into these compounds, they are utilised by plants from the soil through their roots. 

The nitrogen is then used by plants for the synthesis of proteins and other compounds. Animals feeding on these plants get the proteins and nitrogen compounds. When these plants and animals die, the fungi and bacteria present in the soil convert the nitrogenous waste into nitrogenous compounds which are then used by the plants again. 

There are also some bacteria that convert part of them to nitrogen gas which goes back into the atmosphere. This results in the percentage of nitrogen in the atmosphere remaining more or less the same. This cycle is known as the Nitrogen Fixation Cycle.

Microbes: Our Foes

There are certain microbes that can be harmful to other living beings in many ways. The disease-causing microbes are known as pathogens. The microorganisms can spoil food, clothing and leather, and even kill plants and animals.

Disease-causing Microbes in Humans

Harmful microorganisms or pathogens enter our body through the air, water or the food that goes inside us, or by the way of direct contact with an infected person or an animal. The diseases caused by pathogens that spread from an infected being to a healthy person through air, food, water or direct physical contact are known as communicable diseases. Examples of such diseases include tuberculosis, common cold, cholera, chicken pox, etc. 

Suppose a person suffering from a cold sneezes, and droplets of moisture carrying innumerable viruses get spread in the air. The virus may enter the body of a healthy person when he/she breathes close by and transmit the infection. 

We hope this article on the Microbial World has paved the way for you to better understand how microorganisms are good, bad and an indispensable part of our lives. 

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