Class 8 Science - Chapter Microorganisms: Friend and Foe NCERT Solutions | What are the major groups of microorgani
What are the major groups of microorganisms?
There are five major groups of microorganisms which are as follows:
- Bacteria: These are single celled organisms which are harmful as they causes diseases and some of them may be useful as they help. Based on their shape bacteria are of four types:
- Bacillus (rod shape)
- Coccus (spherical shape)
- Spirillum (spiral shape)
- Vibrio (comma shape)
- Fungi: These are non- green plants which consumes their food from dead and decay organic matter. And, they are heterotrophs.
- Protozoa: It is a group of single- celled microorganisms that have animal like characteristics. For example: Amoeba and Paramecium.
- Algae: It is large group of simple plant like organisms. But they do not contain roots, stem or leaves. They can be unicellular or multicellular.
- Viruses: These are smallest microorganisms which reproduce only inside the host body. Outside the host body it behaves like non- living things.
More Questions From Class 8 Science - Chapter Microorganisms: Friend and Foe
- Q:-
What are antibiotics? What precautions must be taken while taking antibiotics?
- Q:-
Write 10 lines on the usefulness of microorganisms in our lives.
- Q:-
Match the organisms in Column I with their action in Column II.
Column I Column II
(i) Bacteria (a) Fixing Nitrogen
(ii) Rhizobium (b) Setting of curd
(iii) Lactobacillus (c) Baking of bread
(iv) Yeast (d) Causing Malaria
(v) A protozoan (e) Causing Cholera
(vi) A Virus (f) Causing AIDS
(g) Producing antibodies - Q:-
Name the microorganisms which can fix atmospheric nitrogen in the soil.
- Q:-
Write a short paragraph on the harms caused by microorganisms.
- Q:-
Tick the correct answer:
(a) Yeast is used in the production of
(i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen(b) The following is an antibiotic
(i) Sodium bicarbonate (ii) Streptomycin (iii) Alcohol (iv) Yeast(c) Carrier of malaria-causing protozoan is
(i) female Anopheles mosquito (ii) cockroach (iii) housefly (iv) butterfly(d) The most common carrier of communicable diseases is
(i) ant (ii) housefly (iii) dragonfly (iv) spider(e) The bread or idli dough rises because of
(i) heat (ii) grinding (iii) growth of yeast cells (iv) kneading(f) The process of conversion of sugar into alcohol is called
(i) nitrogen fixation (ii) moulding (iii) fermentation (iv) infection - Q:-
Fill in the blanks:
(a) Microorganisms can be seen with the help of a ____________.
(b) Blue green algae fix __________ directly from air to enhance fertility of soil.
(c) Alcohol is produced with the help of __________.
(d) Cholera is caused by __________. - Q:-
Can microorganisms be seen with the naked eye? If not, how can they be seen?
Popular Questions of Class 8 Science
- Q:-
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen - Q:-
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called . - Q:-
Give two examples each of situations in which you push or pull to change the state of motion of objects.
- Q:-
Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces. (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction. - Q:-
List conditions under which combustion can take place.
- Q:-
Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F) - Q:-
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth. - Q:-
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called .
(b) Species found only in a particular area is known as .
(c) Migratory birds fly to far away places because of changes. - Q:-
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
- Q:-
What are the different ways in which water gets contaminated ?
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