Ncert – class 8- science – Chapter 2: Microorganisms: Friend and Foe 1 Welcome to your Ncert - class 8- science - Chapter 2: Microorganisms: Friend and Foe 1 1. Which of the following plant diseases is transmitted by seeds? Yellow vein mosaic of Okra Citrus canker All of the above Rust of wheat None 2. Antibiotics are used to treat infections in Plants Humans All of these Animals None 3. Which option is true for antibiotics? medicines that kill or stop the growth of the disease-causing microorganisms. They are produced from bacteria and fungi. Are used to cure a variety of diseases. It is mixed with the feed of livestock and poultry to check microbial infection in animals. None 4. Which of the following is not a way of transmission of pathogens? Consuming contaminated food or water Direct contact with an infected person Vaccinating an individual When bitten by a carrier None 5. Ravi consumed some roadside food along with his friends. He had a severe stomach ache and loose motions on reaching home. What is he suffering from? Fever Food poisoning Dysentery Dehydration None 6. Select the correct combinations based on the application of microorganisms. ,Column AColumn Bi. Brewinga. Microbial decomposition of wastesii. Antibioticsb. Prevention of cholera, TB and hepatitisiii. Vaccinesc. Alcohol and wine i) – b), ii) – a), iii)- d) iv) – c) i) – d) , ii) – c) iii)-a), iv) - b i) – c), ii) – b, iii) – d), iv) – a) i) – c), ii) – d), iii) – a), iv) – b) None 7. What among the following is used as fertiliser when bacteria decompose sewage? Solid waste Carbon dioxide Sludge Soluble substances None 8. Pathogens are microorganisms which Spoil clothing and leather Cause diseases in living organisms Transmit the disease-causing microbes Help us in digesting our food None 9. A patient is suffering from a severe bacterial infection. The best treatment for curing this infection would be the use of: Antibiotic Vaccine Antibody Water None 10. Name the group of microorganisms in which Oscillatoria, Anabaena and Nostoc belong which fix atmospheric nitrogen and improve soil fertility. Blue green algae Symbiotic bacteria Free-living bacteria Fungi None 11. What will happen if we do not preserve food properly? Food will not change its colour or look. Food will become spoilt due to growth of microbes Food will give good odour even after long time Food will remain fresh for long time None 12. Against which disease are children protected under Pulse Polio Program? Tuberculosis Polio Measles Hepatitis None 13. Where is the Rhizobium bacteria found in leguminous plants Stem Leaves Root Flowers None 14. Which bacterium does not fix nitrogen? Azotobacter Clostridium Rhizobium Nitrosomonas None 15. Anil and Sangeeta wanted to do research on which type of preservation is best and effective. Choose the improper combination from below? Anil tried Preservation by Sugar and Sangeeta tried Preservation by Storage and Packing Anil tried Preservation by Common Salt and Sangeeta tried Preservation by chemical method Anil tried Preservation by Oil and Vinegar and Sangeeta tried Preservation by edible oils Anil tried Preservation by Heat and Cold Treatments and Sangeeta tried preservation by sodium benzene None 16. What is the term for the activity occurring when yeast is grown in a sugar solution? Evaporation Fermentation Decomposition Distillation None 17. Which of the following serves as an indirect source of nitrogen in the soil? Human faeces Dead remains of plants Animal droppings All of these None 18. How do herbivores get nitrogen for their body needs? They are able to fix atmospheric nitrogen directly They take the rainwater containing dissolved nitrogen compounds They feed on plants and obtain nitrogen compounds from them. They obtain usable compounds of nitrogen from soil None 19. Identify the ammonifying bacteria. Nitrobacter Nitrosomonas Clostridium Bacillus ramosus None 20. Which of the following are examples of preservatives? Jams and pickles edible Oils and coconut oils Salt and sugar All of the above None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
