Microorganisms

• Bacteria:Bacteria are single- celled microscopic organisms. They can survive under all types of environment, ranging from ice cold climate to hot springs and deserts to marshy lands. Bacteria always live in colonies. They are of spiral shape or rod shape. Bacteria play important role in our life; some bacteria are useful whereas some other are harmful and cause diseases. Bacteria are involved in making of cheese and pickles. Lactobacillus bacteria promote the formation of curd. Antibiotics are also made from bacteria. Apart from this diseases like tuberculosis and typhoid are caused due to bacteria.
• Viruses:Viruses are microscopic infectious agent that acts as non-living outside host cell and inside host cell becomes living and show reproduction. It can affect all kind of organism including animals, plants and bacteria. Common ailments like cold, coughs and influenza (flu) are caused by viruses; serious diseases like chicken pox and polio are also caused by viruses.

• Protozoa:Protozoa had been defined as unicellularprotists with animal-like behaviour like movement. The largest protozoa known are the deep-sea dwellingxenophyophores, which can grow up to 20 cm in diameter.They move around with whip-like tails called flagella, and hair-like structures called cilia,it is responsible for causing diseases like dysentery and malaria in human beings.
• Algae:Algae are a very large and diverse group of simple, typicallyautotrophic organisms, ranging from unicellular to multicellular forms. Most are photosynthetic like plants, and "simple" because their tissues are not organized into many distinct organs found in land plants. The largest and most complex marine forms are called seaweeds.Algae exhibit a wide range of reproductive strategies, from simple, asexual cell division to complex forms of sexual reproduction.Nearly all algae have photosynthetic machinery ultimately derived from cyanobacteria, and so produce oxygen as a by-product of photosynthesis.

Microorganisms are beneficial to us in various ways; they not only prepare curd, bread, cake, wine and medicines for us but also used to increase soil fertility by fixing atmospheric nitrogen. Thus we called them as friendly.

Bacterium lactobacillus multiplies in milk and converts it into curd.

Yeast reproduces rapidly and produces carbon dioxide during respiration. Bubbles of gas fill the dough (mixture of atta or maida and some sugar and water) and increase its volume. This is the basis of using yeast in baking industry.

Fermentation is the process of food processing in which sugar is converted into alcohol by the action of microorganisms. This process is used to produce alcoholic beverages such as wine, beer, and cider. For this purpose yeast is grown on natural sugars present in grains like barley, wheat, rice, crushed fruit juices etc.

Antibiotics are medicines that kill or stop the growth of disease causing microorganisms and they are prepared from microorganisms. For e.g. streptomycin, tetracycline and penicillin are some of the antibiotics prepared from microorganisms like fungi and bacteria.

Vaccines produces antibody in our body to fight against disease causing microbes entering our body. Diseases like cholera, tuberculosis, smallpox and hepatitis can be prevented by vaccination; polio drop given to children is also a vaccine.

The main motto of pulse polio program is to protect children from polio, by providing them with polio drops.

Antibiotics are medicines that kill or stop the growth of disease causing microorganisms and they are prepared from microorganisms. For e.g. streptomycin, tetracycline and penicillin are some of the antibiotics prepared from microorganisms like fungi and bacteria.

Some bacteria and blue green algae are able to fix atmospheric nitrogen into nitrates and nitrates are an important constituent to increase soil fertility. These microbes are generally called biological nitrogen fixers.

Microbes decompose the dead organic wastes of plants and animals converting them into simple substances. These substances are again used by other plants and animals. Thus microbes degrade the harmful and smelly substances and clean up the environment.

Some microorganisms cause diseases in human beings, plants and animals, like somespecies of bacteria causes tuberculosis and typhoid, some species of virus causes common cold and influenza. Some microorganisms also cause spoilage of food, clothing and leather items. Thus we consider some microorganisms are harmful.

Diseases causing microorganisms can enter our body through the air we breathe, water we drink and the food we eat. They can also get transmitted by direct contact through an infected person or carried through an animal.

There are some microbial diseases that can spread from an infected person to a healthy person through air, water, food or physical contact. Such kind of diseases is called communicable disease. For e.g. cholera, chicken pox, tuberculosis.

When a person suffering from common cold sneezes, the fine droplets of moisture containing thousands of viruses are spread in the air, these viruses may enter the body of healthy person while breathing, thus we should keep handkerchief on the mouth and nose while sneezing so that viruses may not spread In the air and enter into healthy person’s body to make him sick.

Houseflies sit on the garbage and animal excreta where pathogens stick to their bodies and these pathogens get transferred to uncovered food when these flies sit on uncovered food items and the person consuming these food fall sick.

Houseflies sit on the garbage and animal excreta where pathogens stick to their bodies and these pathogens get transferred to uncovered food when these flies sit on uncovered food items and the person consuming these food fall sick.

There are some microorganisms that cause disease in animals also like anthrax is a very dangerous human and cattle disease caused by a bacterium. Foot and mouth disease of cattle is caused by a virus.

There are some microorganisms that cause disease in plants like wheat, sugarcane, rice, potato, orange, and apple. Like citrus canker disease caused by bacteria in plant, rust of wheat disease in wheat plant caused by fungi. These diseases reduce the yield of crops and can be controlled by using certain chemicals that kill microbes.

It is because of food poisoning. Food poisoning could be due to the consumption of food spoilt by some microorganisms.

We preserve cooked food at home by using preservatives like salt, sugar and edible oil. Common salt has been used to preserve meat and fish.it is also used to preserve amla, raw mangoes, tamarind, etc. Jams, jellies and squashes are preserved by using sugar. Vegetables, fruits, pickles are often preserved by oil and vinegar.

A mango gets spoilt and rotten after few days but a mango pickle does not spoil for a long period of time because mango pickles contains salt which acts as preservatives and prevent the growth of microorganisms in it.

Preservatives are naturally occurring or synthetically produced substance that are generally used to check the growth of microorganisms. E.g. salt and sugar acts as preservatives in pickles to prevent the growth of microorganisms. Sodium benzoate and sodium metabisulphite are common preservatives,

We preserve cooked food at home by using preservatives like salt, sugar and edible oil. Common salt has been used to preserve meat and fish.it is also used to preserve amla, raw mangoes, tamarind, etc. Jams, jellies and squashes are preserved by using sugar. Vegetables, fruits, pickles are often preserved by oil and vinegar.

We preserve cooked food at home by using preservatives like salt, sugar and edible oil. Common salt has been used to preserve meat and fish.it is also used to preserve amla, raw mangoes, tamarind, etc. Jams, jellies and squashes are preserved by using sugar. Vegetables, fruits, pickles are often preserved by oil and vinegar.

We preserve cooked food at home by using preservatives like salt, sugar and edible oil. Common salt has been used to preserve meat and fish.it is also used to preserve amla, raw mangoes, tamarind, etc. Jams, jellies and squashes are preserved by using sugar. Vegetables, fruits, pickles are often preserved by oil and vinegar.

Boiling kills many microorganisms, thus milk is boiled before storing or consuming. Boiling of milk at about 70°c for 15 to 30 second and then suddenly chilling and its storage destroy all of its microorganisms, and prevent further growth of the microorganisms.

Sealed air tight packets prevent the attack of microbes and protect the food items inside it from getting spoiled and toxic.

The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms.Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, ammonium (NH4+), nitrite (NO2-), nitrate (NO3-), nitrous oxide (N2O), nitric oxide (NO) or inorganic nitrogen gas (N2), atmospheric nitrogen needs to be processed to be used by plants and animals. Some bacteria and blue green algae present In soil fix atmospheric nitrogen into nitrates which is used by plants from the soil through their root systemnitrogen is then used for synthesis of plant proteins and other compounds,when plants and animals die bacteria and fungi present in soil convert the nitrogenous waste into nitrogen compounds to be used by plants again, some bacteria converts some part of them into nitrogen gas which goes back into the atmosphere, thus percentage of nitrogen in atmosphere remains more or less constant.