MICROORGANISM
(i) Organisms which are too small to be seen by the eye, especially one celled organism is named microorganisms or microbes.
(ii) Microorganisms are classified into four major groups- bacteria, fungi, protozoa and a few algae.
Virus
(iii) Viruses are microscopic. They reproduce only inside the cells of the host organism, which can be a bacterium, plant or animal.
Where do Microorganisms Live:
(i) Microorganisms is also single celled (bacteria, some algae and protozoa) or multi cellular (algae and fungi) can survive under every type of environment, starting from ice cold climate to hot springs and deserts to marshy lands.
(ii) they're also found inside the bodies of other organisms including humans.
(iii) Growth of some microorganisms depends on other organisms while other organisms exist freely.
(iv) Microorganisms like amoeba can live alone, while fungi and bacteria may board colonies.
Microorganisms and Us:
Some of Microorganisms are beneficial in many ways while some others are harmful and cause diseases.
Friendly Microorganisms:
Microorganisms are used for various purposes.
(i) Some microorganisms are utilized in the assembly of curd, bread and cake.
(ii) Some microorganisms are used for the assembly of alcohol since ages.
(iii) they're also utilized in cleaning of the environment as composers. for instance, the organic wastes (vegetable peels, remains of animals, faeces, etc.) are weakened into harmless and usable substances by bacteria.
(iv) In agriculture fields, microorganisms are wont to increase soil fertility by fixing nitrogen.
Commercial Use of Microorganisms:
(i) for big scale production of alcohol, wine and carboxylic acid (Vinegar) Microorganisms are used
(ii) For commercial production of alcohol and wine yeast is grown on natural sugars present in grains like barley, wheat, rice and crushed fruit juices, etc.
Medicinal Use of Microorganisms:
(i) Whenever we fall ill the doctor may give us some antibiotic tablets, capsules or injections like peenicillin which are made of microorganism.
(ii) nowadays the medicines produced from Bactria and fungi kill or stop the expansion of the disease-causing microorganisms. Such medicines are called antibiotics.
(iii) Streptomycin, tetracycline and erythromycin medicines which are made up of fungi and bacteria are a number of the commonly known antibiotics.
(iv) The antibiotics are made by growing specific microorganisms and are wont to cure a spread of diseases. Antibiotics should be taken only on the recommendation of a professional doctor.
(v) Antibiotics are even added with the feed of livestock and poultry for checking microbial infection in animals.
(vi) Microorganisms are wont to control many plant diseases.
Vaccine:
(i) When a disease-carrying microbe enters our body, the antibodies produced by our body fight with the invader. If microbes enter again, the body also remembers that a way to fight with the microbes.
(ii) If dead or weakened microbes are injected in an exceedingly healthy body, the body fights and kills them by producing suitable antibodies.
(iii) The antibodies remain within the body for safeguarding from the disease causing microbes. this can be how a vaccine works.
(iv) Several diseases like cholera, tuberculosis, smallpox and hepatitis will be prevented by vaccination.
Increasing Soil Fertility:
(i) Some bacteria and blue chlorophyte are able increase the fertility of soil by fix nitrogen from the atmosphere to complement soil with nitrogen. These microbes are commonly called biological nitrogen fixers.
Cleaning the Environment:
At the time of constructing manure, we collect wastes of plants, vegetables and fruits from nearby houses and gardens. They put them in an exceedingly pit meant for waste disposal. After your time, it decomposed by microorganisms and gets converted to manure. By this method environment is cleaned.
Harmful Microorganisms:
(i) a number of microorganisms are harmful in many ways.
(ii) In people in general, plants and animals, a number of the microorganisms cause diseases. Such disease-causing microorganisms are called pathogens.
(iii) Food, clothing and leather are spoiled because of some harmful microorganisms
Disease— causing Microorganisms in Humans:
(i) Pathogens enter our body through the various way like air once we breathe, the water once we drink or the food once we eat. they will also get transmitted by direct contact with an infected person or carried through an animal.
(ii) Microbial diseases like cholera, respiratory illness, chicken pox and tuberculosis which will spread from an infected person to a healthy person through air, water, food or physical contact are called communicable diseases.
(iii) There are some insects and animals which act as carriers of disease causing microbes. for instance housefly is one such carrier that flies sit on the rubbish and animal excreta etc. Pathogens keep on with their bodies. When these flies sit on uncovered food they transfer the pathogens. Whoever eats the contaminated food is probably going to urge sick. Some more samples of carrier microbes are the feminine Anopheles mosquito, which carries the parasite of malaria. Female Aedes mosquito acts as carrier of dengue virus.
(iv) All mosquitoes breed in water. So, one shouldn't let water collect anywhere like in coolers, tyres, flower pot etc. By keeping the environment clean and dry we are able to prevent mosquitoes from breeding
Some of microorganisms not only cause diseases in humans and plants, but also in other animals. For example: anthrax is an example of dangerous human and cattle disease caused by a bacterium. Foot and mouth disease of cattle is caused by an endemic.
Disease-causing Microorganisms in Plants:
Some of microorganisms cause diseases in plants like wheat, rice, potato, sugarcane, orange, apple et al.. These diseases reduce the yield of crops. they will be controlled by the utilization of certain chemicals or pesticides which kill the microbes, which affect the yield the crops.
Some Common Plant Diseases caused by Microorganisms
Food Poisoning:
Food poisoning in humans may be because of the consumption spoiled food by some microorganisms. Microorganisms that grow on our food produce toxic substances and make the food poisonous causing serious diseases. So, it's important that we preserve food to stop it from being spoilt by the microorganisms.
Food Preservation:
Microorganisms spoil our food. Spoiled food emits bad smell and encompasses a bad taste and adjusted colour. Here some common methods to preserve food in our homes.
a. Chemical Method:
(i) Preservatives like Salts and edible oils are the common chemicals generally accustomed check the expansion of microorganisms.
(ii) We add salt or acid preservatives to pickles to stop the attack of microbes. benzoate and sodium meta bisulphite are common preservatives which are utilized in the jams and squashes to test their spoilage.
b. Preservation by Common Salt:
(i) To preserve meat and fish for ages, common salt is employed. Meat and fish are covered with dry salt to test the expansion of bacteria.
(ii) Salting is additionally accustomed preserve amla, raw mangoes, tamarind, etc.
c. Preservation by Sugar:
(i) Sugar is employed for preserving jams, jellies and squashes are preserved.
(ii) It reduces the moisture content which inhibits the expansion of bacteria which spoil food.
d. Preservation by Oil and Vinegar:
(i) Oil and vinegar are accustomed prevent spoilage of pickles because bacteria cannot sleep in such an environment.
(ii) Vegetables, fruits, fish and meat are often preserved by this method.
e. Heat and Cold Treatments:
(i) Boiling of milk kills many microorganisms, then it's stored or used.
(ii) We keep our food within the refrigerator. temperature inhibits the expansion of microbes.
(iii) milk is taken without boiling because it is free from harmful microbes. The milk is heated to about 700C for 15 to 30 seconds then suddenly chilled and stored. By doing so, this process prevents the expansion of microbes. This process was discovered by biologist. it's called pasteurization.
f. Storage and Packing:
Dry fruits and even vegetables are sold in sealed air tight packets to stop the attack of microbes.
Nitrogen Fixation:
(i) Rhizobium is involved within the fixation of nitrogen in leguminous plants (pulses).
(ii) Nitrogen also gets fixed through the action of lightning. But the number of nitrogen remains constant within the atmosphere.
Nitrogen Cycle:
(i) Nitrogen is one in all the essential constituents of all living organisms as a part of proteins, chlorophyll, nucleic acids and vitamins, available 78% in our surroundings. Bacteria and blue algae present within the soil for fixing nitrogen from the atmosphere then convert into compounds of nitrogen.
(ii) After this, usable compounds is utilised by plants from the soil through their system. These compounds are then used for the synthesis of plant proteins and other compounds. Animals feeding on plants get these proteins and other nitrogen compounds.
(iii) When plants and animals die, bacteria and fungi present within the soil convert the nitrogenous wastes into nitrogenous compounds to be utilized by plants again. Certain other bacteria convert some a part of them to nitrogen gas which fits into the atmosphere. As a result, the share of nitrogen within the atmosphere remains more or less constant.
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