Free Worksheets, Lessons, Quizzes
Free Worksheets, Lessons, Quizzes
A microorganism or microbe is a microscopic organism, which can only be seen with a microscope. Bacteria, viruses and fungi are the main microorganisms that we know. Mostly, we know the bad effects of microorganisms, but do you know there are microorganisms, which are very useful to us? This lesson describes you all about useful microorganisms.
Waste matter carried away in gutters or drains is called sewage.
Waste pipes that carry away sewage are called sewers.
1) Waste water passes through filter beds.
2) These filter beds contain sand and gravel.
3) Sand and gravel are covered by microorganisms.
4) As waste water passes over sand and gravel in the filter beds, microorganisms break down the waste materials quickly.
5) So the waste water can be cleaned and put into a river or a sea.
Yeast
Yeast cells grow rapidly (quickly) if they have food and moisture. When they are warm and moist, the tiny yeast cells feed on the sugar which is in the bread dough and make carbon dioxide and alcohol.
1) Carbon dioxide gas
2) Alcohol
1) The carbon dioxide makes the dough rise.
2) So that the bread is packed with little bubbles and has a light texture.
The carbon dioxide and alcohol evaporate away when the bread dough is baked.
Yeast
1) Water
2) Barley
3) Hops (A kind of a dried flower added to beer to get the bitter taste)
4) Sugar
5) Yeast
Water, barley, hops and sugar are mixed. A special type of yeast is added to the mixture. And the mixture is kept warm. The yeast feeds on the sugar and makes alcohol and carbon dioxide.
1) Carbon dioxide gas
2) Alcohol
Crushed grapes
It grows wild on the skin of the grapes.
The yeast feeds on the sugar in the grape juice and produces alcohol with carbon dioxide.
1) Carbon dioxide gas
2) Alcohol
1) Milk
2) Bacteria
The harmless bacteria are added to the boiling milk. And the milk is kept warm. Bacteria grow and multiply in warm milk by feeding on the sugar called, ‘lactose’ in the milk. Now bacteria break down lactose sugar into ‘lactic acid’. The lactic acid changes part of the milk solid or thick. Bacteria don’t eat this solid or thick part of milk and this stops any harmful bacteria growing. Some chemicals produced by the bacteria give the solid part of the milk a particular flavour.
Fruit or flavouring may be added to get the right taste of yoghurt.
It is a kind of English blue cheese.
1) A fungus or mould is added to the cheese while it is ripening.
2) This harmless fungus makes the cheese look blue and gives it a special flavour.
1) To make vinegar
2) To make antibiotics
3) To extract metals from the rocks
E.g. – The valuable metal ‘uranium’ is extracted in this way
4) To make leather
E.g. – Microbes clean the skins of dead animals before they are turned into leather
5) To clean oil tanks
E.g. – When the oil tanks on ships and in oil refineries need cleaning, some bacteria are used to feed on the waste oil of the tanks. When all the oil has been decomposed away, the tanks can then be washed out.
6) Decomposers
Inside a pile of dead leaves are millions of tiny bacteria. These bacteria feed on the leaves and break them down into nutrients. The nutrients go back into the soil where they can be used by plants.
A natural chemical made from a mould or bacterium that can kill microorganisms and cure bacterial infections (diseases).
1) They can be active against one or more bacteria.
2) They can kill bacteria.
3) They can slow down the growth of bacteria.
In 1928
A British scientist called Alexander Fleming.
Penicillin
A mould called Penicillium
By changing the substances produced by the mould called ‘Penicillium’ into a drug.
Septicemia (An infection of the bloodstream caused by microorganisms)
Liquids such as milk are heated until all the harmful germs are killed. This is called pasteurization. Pasteurization is one of the ways of preserving foods.
The liquid or milk is heated to 600C (60 degrees Celsius) and held there for at least thirty minutes and then cooled quickly. In this way all the harmful germs in the liquid can be killed.
In 1864
A French man named Louis Pasteur
The process of pasteurization is named after Louis Pasteur in recognition of his great contribution to food safety.
Grocery items like,
1) Milk
2) Juice
3) Non-dairy milk and other similar food products.
In conclusion, useful microorganisms are indispensable in our life. Without useful microorganisms, things would be very hard and life would not be very easy. Hope you learned a great deal of facts about useful microorganisms.