Microorganisms – Friends and Foe
Microorganisms are too small and are not visible to the unaided eye.
Microorganisms are found in
air, water and in the bodies of plants and animals.
Diseases like dysentery and malaria are caused by
protozoans whereas typhoid and tuberculosis (TB) are bacterial diseases.
Microorganisms may be
unicellular or multicellular.
Microorganisms have been used for the production of alcohol since ages they are also used in cleaning up of the environment.
Microorganisms can live in all kinds of environment, ranging from ice cold climate to hot springs and deserts to marshy lands.
amoeba can live alone, while fungi and bacteria may live in colonies.
Viruses are also microscopic they reproduce only inside the cells of the host organism, which may be a bacterium, plant or animal.
Viruses are quite different from other microorganisms. They reproduce only inside the host organism; bacterium, plant or animal cell.
Curd contains several microorganisms. Of these, the bacterium
Lactobacillus promotes the formation of curd. It multiplies in milk and converts it into curd.
Microorganisms play an important role in our lives. Some of them are beneficial in many ways whereas some others are harmful and cause diseases.
These days a number of antibiotics are being produced from
bacteria and fungi Streptomycin, tetracycline and erythromycin are some of the commonly known antibiotics.
Microorganisms are used for the large scale production of
alcohol, wine and acetic acid (vinegar)
Antibiotics are even mixed with the feed of livestock and poultry to check microbial infection in animals. They are also used to control many plant diseases.
vaccines are made on a large scale from microorganisms to protect humans and other animals from several diseases.
Some bacteria are able to fix nitrogen from the atmosphere to enrich soil with nitrogen and increase its fertility. These microbes are commonly called
biological nitrogen fixers.
decompose dead organic waste of plants and animals converting them into simple substances.
Microorganisms can be used to degrade the harmful and smelly substances and thereby clean up the environment.
The plant waste is always converted into manure by the action of
The disease causing micro organisms are called as
Pathogens enter our body through the air we breathe, the water we drink or the food we eat.
Pathogens can also get transmitted by direct contact with an infected person or carried through an animal.
Robert Köch (1876) discovered the bacterium (Bacillus anthracis) which causes anthrax disease.
Anthrax is a dangerous human and cattle disease caused by a bacterium.
microorganisms cause diseases in plants like wheat, rice, potato, sugarcane, orange, apple and others. the diseases reduce the yield of crops.
Food poisoning could be due to the consumption of food spoilt by some microorganisms.
Microorganisms that grow on our food sometimes produce
toxic These make the food poisonous causing serious illness and even death.
Sodium benzoate and sodium metabisulphite are common preservatives.
Preservatives are also used in the jams and squashes to check their spoilage.
Common salt has been used to preserve meat and fish for ages.
Meat and fish are covered with dry salt to check the growth of
Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.
oil and vinegar prevents spoilage of pickles because bacteria cannot live in such an environment.
These days’ dry fruits and even vegetables are sold in sealed air tight packets to prevent the attack of
Our atmosphere has 78%
Some microorganisms reside in the root nodules of
leguminous They can fix nitrogen from air into soil and increase the soil fertility.
Nitrogen is one of the essential constituents of all living organisms as part of proteins, chlorophyll, nucleic acids and vitamins.
nitrogen gets fixed through the action of lightning.
bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert into compounds of nitrogen.
When plants and animals die,
bacteria and fungi present in the soil convert the nitrogenous wastes into nitrogenous compounds to be used by plants again.
bacteria convert compounds of nitrogen present in the soil into nitrogen gas which is released to the atmosphere.
When nitrogen is converted into these usable compounds, it can be utilized by plants from the soil through their
Nitrogen is then used for the
synthesis of plant proteins and other compounds.