Lakhmir Singh & Manjit Kaur: Microorganisms Friends And Foe- 1 | Lakhmir Singh & Manjit Kaur Solutions: Class 8 Science PDF Download

Q.1. Name the instrument (or device) which is needed to see the microorganisms.

Microscope is needed to see the micro-organisms.

Q.2. What is the name of micro-organisms which reproduce only inside the living cells of other organisms?

Viruses are the smallest micro-organisms which reproduce only inside the living cells of other organisms.

Q.3. What are the major groups of micro-organisms?

There are five major groups of micro-organisms. These are: Bacteria, viruses, Protozoa, some fungi and Algae.

Q.4. Name any two human diseases caused by bacteria.

Typhoid and Cholera are caused by bacteria in human beings.

Q.5. Name any two human diseases caused by viruses.

The human diseases such as common cold and influenza are caused by viruses.

Q.6. Name any two human diseases caused by protozoa.

The human diseases amoebic dysentery and malaria are caused by protozoans.

Q.7. Name any two human diseases caused by fungi.

Diseases athlete’s food and ring worm are caused by fungi.

Q.8. Which micro-organism is utilized in making curd from milk?

 Lactobacillus bacterium is utilized in making curd from milk.

Q.9. Name the -micro-organism which is used for the large-scale production of alcohol.

Yeast is used for the large-scale production of alcohol.

Q.10. Name any two antibiotics.

Streptomycin and erythromycin are two commonly known antibiotics which are made from fungi and bacteria.

Q.11. Name an antibiotic extracted from fungus (mould). Name the fungus.

An antibiotic Penicillin was extracted from fungus (mould) by Alexander Fleming in 1929. This antibiotic was made from the fungus called penicillium.

Q.12. Name any four diseases which can be prevented by vaccination.

Several diseases including tuberculosis, smallpox, cholera and hepatitis can be prevented by vaccination.

Q.13. Name the scientist who discovered the-vaccine for 'smallpox.

Edward Jenner discovered the vaccine for smallpox in 1978.

Q.14. Name the scientist who discovered 'penicillin'.

Alexander Fleming discovered the antibiotic “Penicillin” in 1929.

Q.15. State an important function performed by blue-green algae.

Blue green algae fix the atmospheric nitrogen to enrich soil with nitrogen and hence, increase soil fertility.

Q.16. Name one 'biological nitrogen-fixer'.

Blue green algae are known as 'biological nitrogen-fixer' as they fix the atmospheric nitrogen.

Q.17. Name two common insects which act as carriers of disease-causing microorganisms (or disease-causing microbes).

The two common insects which act as carriers of disease-causing microorganisms (or disease-causing microbes) are housefly and mosquito.

Q.18. Name any two diseases spread by housefly. 

Diseases cholera and tuberculosis spread by housefly.

Q.19. Name the insect which is the carrier of parasite of malaria. 

The carrier of parasite of malaria is Female Anopheles mosquito.

Q.20. Name the insect which carries dengue virus. 

Female Aedes mosquito carries dengue virus.

Q.21. Which of the two spreads dengue: mosquito or housefly? 

Female Aedes mosquito acts as a carrier of dengue virus.

Q.22. Name two diseases spread by mosquitoes.

Malaria and dengue spread by mosquitoes.

Q.23. Name the microbe which causes malaria disease. 

Protozoa Plasmodium causes malaria disease.

Q.24. Name one disease which spreads by breathing in air containing microorganisms. 

Tuberculosis disease spreads by breathing in air containing micro-organisms.

Q.25. Name one disease which spreads through insect bites. 

Malaria disease spreads through insect bites.

Q.26. Name one disease which spreads through infected food or water. 

Cholera disease spreads through infected food or water.

Q.27. Name the causative micro-organisms of the following animal diseases:
(a) Foot and mouth disease
(b) Anthrax

(a) Foot and mouth disease is caused by a virus.
(b) Anthrax disease is caused by a bacterium.

Q.28. Name two food materials which are preserved by sun-drying method in our homes.

Vegetables like methi leaves and spinach are preserved by sun-drying method in our homes.

Q.29. Name two food materials which are preserved by using common salt. 

Meat and fish are preserved by using common salt.

Q.30. Name two food materials which can be preserved by using sugar.

Jams and jellies are preserved by using sugar.