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? Citrus canker Rust of wheat All of the above Yellow vein mosaic of Okra None 2. Against which disease are children protected under Pulse Polio Program? Tuberculosis Hepatitis Polio Measles None 3. What is the term for the activity occurring when yeast is grown in a sugar solution? Distillation Decomposition Fermentation Evaporation None 4. Antibiotics are used to treat infections in All of these Plants Humans Animals None 5. How do herbivores get nitrogen for their body needs? They feed on plants and obtain nitrogen compounds from them. They obtain usable compounds of nitrogen from soil They take the rainwater containing dissolved nitrogen compounds They are able to fix atmospheric nitrogen directly None 6. Which option is true for antibiotics? They are produced from bacteria and fungi. medicines that kill or stop the growth of the disease-causing microorganisms. 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 7. Which of the following serves as an indirect source of nitrogen in the soil? Animal droppings All of these Dead remains of plants Human faeces None 8. Which of the following is not a way of transmission of pathogens? Vaccinating an individual Direct contact with an infected person Consuming contaminated food or water When bitten by a carrier None 9. 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 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 Anil tried Preservation by Sugar and Sangeeta tried Preservation by Storage and Packing None 10. Pathogens are microorganisms which Spoil clothing and leather Help us in digesting our food Cause diseases in living organisms Transmit the disease-causing microbes None 11. 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) – c), ii) – d), iii) – a), iv) – b) i) – c), ii) – b, iii) – d), iv) – a) i) – d) , ii) – c) iii)-a), iv) - b None 12. Which of the following are examples of preservatives? Salt and sugar Jams and pickles edible Oils and coconut oils All of the above None 13. What among the following is used as fertiliser when bacteria decompose sewage? Soluble substances Carbon dioxide Sludge Solid waste None 14. Identify the ammonifying bacteria. Clostridium Nitrosomonas Nitrobacter Bacillus ramosus None 15. Where is the Rhizobium bacteria found in leguminous plants Leaves Root Stem Flowers None 16. What will happen if we do not preserve food properly? Food will become spoilt due to growth of microbes Food will remain fresh for long time Food will give good odour even after long time Food will not change its colour or look. None 17. 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 Dehydration Dysentery Food poisoning None 18. A patient is suffering from a severe bacterial infection. The best treatment for curing this infection would be the use of: Water Vaccine Antibody Antibiotic None 19. Name the group of microorganisms in which Oscillatoria, Anabaena and Nostoc belong which fix atmospheric nitrogen and improve soil fertility. Blue green algae Fungi Free-living bacteria Symbiotic bacteria None 20. Which bacterium does not fix nitrogen? Nitrosomonas Clostridium Rhizobium Azotobacter 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.
