Microorganisms Class 8 Notes

CBSE Class 8 Science Chapter 2 Notes: Microorganisms

If you observe a drop of water from the pond through a microscope, you will see a lot of tiny rounded structures. These tiny creatures are known as microbes or microorganisms. They are all around us and are so small in size that they cannot be seen with bare human eyes. Microbes are classified into four groups as:

  • Protozoa
  • Bacteria
  • Fungi
  • Algae

The class 8 science chapter 2 discusses the characteristics of microorganisms around us. Following are a few important points of microorganisms:

  1. Micro-organisms can either be unicellular or multicellular. They live in environments ranging from deserts to marshy lands. A few microbes grow on other animals and the others exist freely
  2. A virus, although a microbe, is different from other microorganisms. They reproduce only inside a host cell such as plant and animal cell.
  3. A few microbes are useful while others like protozoans cause serious diseases like malaria.
  4. Useful microorganisms decompose dead animals and plants and keep the environment clean and they also fix nitrogen from the air into the soil increasing the fertility of the soil.
  5. Microorganisms are used for the preparation of curd, bread, cake, and alcohol.

Microorganisms play an important role in our lives and are beneficial to us in many ways, whereas, a few microorganisms are harmful and can cause deadly diseases. In chapter 2 of class 8 science, you will study about them in detail.

Microorganism: Friend And Foe Class 8 MCQ

  1. Carrier of malaria-causing protozoan is _____.
    1. butterfly
    2. cockroach
    3. female Anopheles mosquitos
    4. Housefly

Answer: female Anopheles mosquitos

  1. The bread or Dosa dough rises because of _____.
    1. grinding
    2. heat
    3. the growth of yeast cells
    4. kneading

Answer: the growth of yeast cells

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