Microorganisms are not similar to each other, they differ not only in size but also in structure, habitat, metabolism and several other characteristics.
As the name suggests those organisms that are seen through a microscope or microscopic organisms are known as microorganisms or microbes. They are found all around us and you will be amazed to know that they are found inside our bodies also. So, we can say that microorganisms are so small that usually, we require a microscope to see them.
Let us tell you that the vast majority of microorganisms do not pose any harm or threat to humans, plants or animals. In fact, they work alongside humans to make the world go round like they help in decomposition, decay and also help us to digest food in our body. But we can't ignore the fact that there are some microorganisms which pose a negative impact or harm us like they cause illness, bad odours, can even damage certain products, surfaces, etc. Some common names of microorganisms that we mostly hear are Salmonella, E.Colli, MRSA, Malaria, Bird flu.
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Classification of Microorganisms
There are various types of microorganisms like bacteria, fungi, viruses, algae, archaea, and protozoa.
Bacteria: Bacteria are the most common microorganism that we hear most in our daily lives Isn't it! They are a member of prokaryotes. They do not have a nucleus inside the cell and do not contain organelles. So, mainly they are specialised cellular organs. Bacteria consist of two classes namely Gram-positive bacteria which consists thicker cell wall and another is Gram-negatives which have a thinner layer that is sandwiched between an inner and outer membrane.
Note: It is said that Bacteria does not pose any harm and can live harmlessly within the human body and are the most successful organism on the Earth. They also help in body function like digestion. Few bacteria may be dangerous also.
Fungi: They are eukaryotes that have defined nucleus and organelles. Do you know that the cells of fungi are larger than prokaryote that is bacteria? When fungi achieved a certain level of growth, they are visible via eye like a mould on bread.
Fungi are divided into three main groups:
- Moulds that display thread-like growth and are multicellular in structure.
- Yeasts are non-filamentous and can be single-celled.
- Mushrooms which has a fruiting body for the production of spores.
Fungus consists of pathogens that can cause disease in plants. In fact in the food industry, for production of beer, etc. fungi are used.
Viruses: According to various experts viruses are not living organisms. They consist of nucleic acid that is DNA or RNA and a protein coat. Basically, a virus requires a host cell for replication. The virus enters human beings and enters the cell where they replicate.
It depends upon the immune system of the body. If the immune system is weak then the virus may affect the human being and may cause diseases like a common cold, influenza, etc. In fact, some viruses may cause permanent and irreversible damage to the cells of human beings for example HIV.
Algae: According to some definitions algae consists of prokaryotes and eukaryotes both. Algae, unlike other microorganisms, are photosynthesisers and are typically found in marine environments. Prokaryotic algae are known as Cyanobacteria or blue-green algae. But some say that algae are eukaryotes only that is they are small aquatic plants.
So, now you may have come to know about microorganisms and their types.
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