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CBSE Class 8  >  Class 8 Test  >  Online Quizzes   >  Important Questions Test: Microorganisms : Friend Or Foe - 1 - Class 8 MCQ

Microorganisms : Friend Or Foe - 1 - Free MCQ Test with solutions,


MCQ Practice Test & Solutions: Important Questions Test: Microorganisms : Friend Or Foe - 1 (20 Questions)

You can prepare effectively for Class 8 Online Quizzes for Class 8 with this dedicated MCQ Practice Test (available with solutions) on the important topic of "Important Questions Test: Microorganisms : Friend Or Foe - 1". These 20 questions have been designed by the experts with the latest curriculum of Class 8 2026, to help you master the concept.

Test Highlights:

  • - Format: Multiple Choice Questions (MCQ)
  • - Duration: 20 minutes
  • - Number of Questions: 20

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Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 1
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Name the unicellular or multicellular microorganism which is found in water.

Detailed Solution: Question 1

Because most of these micro-organisms are green in color, while few may be yellowish-brown. Algae are also diverse and may either be Unicellular and Multicellular. Some of the most common forms of algae that may be found in pond water include sphingomonas, euglena as well as Chlamydomonas.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 2
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Lactobacillus is an example of ___________ .

Detailed Solution: Question 2

Lactobacillus is a type of bacteria. There are many species of lactobacillus. These are "friendly" bacteria that normally live in our digestive, urinary, and genital systems without causing disease.

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Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 3
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Penicillium and Aspergillus are examples of __________ .

Detailed Solution: Question 3

Fungi are multicellular, heterotrophic microorganisms found in colonies. Hence, Penicillium and Aspergillus are examples of fungi.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 4
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Which of the following diseases is caused by bacteria?

Detailed Solution: Question 4

  • Tuberculosis is an air-borne disease caused by the bacterial species Mycobacterium tuberculosis.

  • Polio, dengue, and chickenpox are viral diseases caused by Picornavirus, Flavivirus, and chickenpox virus respectively.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 5
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Some plants have nitrogen-fixing bacteria in their root nodules. What are these bacteria called?

Detailed Solution: Question 5

Leguminous plants like peas have nitrogen-fixing bacteria called Rhizobium in their root nodules. Rhizobium helps in converting atmospheric nitrogen into ammonia that can be utilized by the pea plant for its nutrition. Other bacteria like Nitrosomonas and Azotobacter are free-living soil bacteria that also help in nitrogen fixation.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 6
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In order to take precautionary steps to control dengue, we must take measures to stop the breeding of

Detailed Solution: Question 6

Dengue is caused by a virus and is spread by a species of mosquito called Aedes. The spread of this disease can be prevented by using mosquito nets, repellents and by control of the breeding of mosquitoes by not allowing water stagnation in our surroundings.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 7
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Partial sterilization of a product such as milk at a high temperature is known as:

Detailed Solution: Question 7

Pasteurization is a process in which milk is heated to about 70oC for 15 to 30 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur and hence is called pasteurization.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 8
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Living organisms which are invisible to the naked eye are called _________.

Detailed Solution: Question 8

Living organisms that are invisible to the naked eye are called microorganisms. Microorganisms are too small to be seen with our naked eyes. They can be seen only through a device known as a microscope.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 9
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Which of the following is a communicable disease?

Detailed Solution: Question 9

Chickenpox is a communicable disease. Communicable diseases are caused by pathogens and can be spread from one person to another through water, air, soil, etc.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 10
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Vaccines are made up of

Detailed Solution: Question 10

A vaccine is a biological preparation containing weakened or dead microbes. It is introduced into a healthy person’s body so that it can produce antibodies against the disease-causing microbes. Vaccines can be injected or administered orally.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 11
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The bacterium present in curd is:

Detailed Solution: Question 11

Lactobacillus is the microorganism present in curd. This bacterium converts milk into the curd at 30 to 40oC.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 12
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While baking cakes, yeast reproduces rapidly and produces ___ gas.

Detailed Solution: Question 12

While baking cakes, yeast reproduces rapidly and produces carbon dioxide gas. This gas is responsible for the spongy texture of the cake.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 13
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Which of the following diseases can be cured using antibiotics?

Detailed Solution: Question 13

Antibiotics are medicines that kill or stop the growth of disease-causing microorganisms. Streptomycin, tetracycline, and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria. Antibiotics are mostly effective against bacterial diseases. Among the diseases given, only typhoid is caused by bacteria, i.e., Salmonella typhi, whereas all the other diseases are caused by protozoa or viruses.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 14
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Which organisms are microscopic and dependent on host organisms for reproduction?

Detailed Solution: Question 14

Viruses are non-cellular microorganisms composed of protein, nucleic acids, and lipids. Viruses are considered both living and non-living organisms. They are active inside host cells and reproduce inside them by infecting living cells. Outside a host, it is considered non-living as it does not have cellular machinery of its own.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 15
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An infectious disease is ___________ .

Detailed Solution: Question 15

Infectious diseases are caused by any pathogenic microorganisms such as bacteria, viruses, parasites, or fungi. The diseases can be spread, directly or indirectly, from one person to another.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 16
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Which among the following statements is not associated with food preservation?

Detailed Solution: Question 16

  • Food preservation is the prevention of the growth of bacteria, fungi, and other microorganisms in food items.

  • There are different methods of preserving food. For example, packaging, smoking, drying, pickling, etc.

  • Food preservation also prevents spoilage of food and increase their shelf life.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 17
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Which one of the following is not produced by the process of fermentation?

Detailed Solution: Question 17

The breakdown of carbon-containing substances like carbohydrates in the absence of oxygen by microorganisms like yeast and bacteria is termed as fermentation. Fermentation is involved in making bread, vinegar, yoghurt, wine, cider, cocoa, cheese, etc.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 18
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A plant disease called citrus canker is caused by a _________.

Detailed Solution: Question 18

Citrus canker is a plant disease caused by bacteria. Its mode of transmission is through the air.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 19
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Which among the following pathogens causes cholera?

Detailed Solution: Question 19

Cholera is caused by bacteria. It spreads through contaminated food and water. It can be prevented by consuming properly cooked food and drinking boiled water.

Important Questions Test: Microorganisms : Friend Or Foe - 1 - Question 20
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Alcohol is produced with the help of

Detailed Solution: Question 20

The type of alcohol in the alcoholic drinks we drink is a chemical called ethanol. To make alcohol, you need to put grains, fruits or vegetables through a process called fermentation (when yeast or bacteria react with the sugars in food - the by-products are ethanol and carbon dioxide).

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About this Class 8 Practice Test

This test contains 20 MCQs on Important Questions Test: Microorganisms : Friend Or Foe - 1 with detailed solutions for each question. It is part of the Online Quizzes for Class 8 course on EduRev, designed to align with the current Class 8 syllabus. Each solution explains not just the correct answer but also gives you an understanding of the topic — not just to attempt the question but also help you prepare for the exam with practice.

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