Preservatives, prevent the spoilage of foods leaves for a long time from microbial infection. We used in kitchen:

Preservatives (vinegar, common salt, oil) prevent the spoilage of foods leaves for a long time from microbial infection.

Which of the following reproduces only inside a host cell?

Virus is a micro-organism, which is in an inactive or dead from outside the body of a host. It reproduces or replicates only when it enters a host and reaches its cells.

Paheli wants to know the incorrect statements, given by her teacher as home-work?

Carrier or vector are the modes of transmission of a disease. Rest of all are correct. Hence, you answer will be option [C].

There are given some statements about “microorganisms”. Choose the correct statements:

Paramecium is a unicellular organism, a protozoan found in water bodies. Spirogyra is a filamentous green spiral in shape, ground as green slimy mats on surface of water bodies. Penicillin antibiotic is extracted from aspergillus fungi.

Paheli wants to know the non-benefits about microorganisms?

Rust of wheat is caused by fungi which is a disease in plants. Therefore, option [B] is non-benefits of microorganisms.

What do you mean by communicable diseases?

Communicable diseases can spread from infected person to others when any person cough or sneeze. When a person suffering from common cold sneezes, fine droplets of moisture carrying thousands of viruses are spread in the air. The virus may enter the body of a healthy person while breathing. It can spread by street food also.

Paheli wants to pick out the incorrect sentences from the given statements:

Foot and mouth disease is caused in cattle by a virus. Wheat of rust is a fungal disease in plants. Yellow vein mosaic of bhindi (okra) is a viral disease in plants.

Boojho wants to know the incorrect sentences about bacteria?

Bacteria can feed and respire. But viruses are the intermediate of living and non-living things. Viruses reproduced when it enters any host body.

Boojho wants to know the incorrect sentences about viruses?

Here, all the statements are correct. Hence, your answer will be option [D].

Consider the following statement and choose the incorrect sentences.

Entamoeba is a protozoan which causes a disease known as amoebic dysentery and plasmodium is a protozoan which causes a disease called malaria in humans.

A disease “Tetanus” is caused by which bacteria:

In 1975 John Bartlett, the discovery of Clostridium difficile and he identified it as the leading cause of hospital-associated infections. Tetanus is caused by a toxin made by spores of bacteria, Clostridium tetani, found in soil, dust and animal feces. When the spores enter a deep flesh wound, they grow into bacteria that can produce a powerful toxin, tetanospasmin. The toxin impairs the nerves that control your muscles (motor neurons).

Paheli wants to write some correct statements. Would you help her?

Here, all the options are correct. Hence, your answer will be option [D].

In which of the following human diseases are caused by viruses?

Measles is caused by infection with the rubeola virus. The virus lives in the mucus of the nose and throat of an infected child or adult. Poliomyelitis is an acute communicable disease of humans. Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV). The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab over.

Choose the way which are not responsible for the spread of communicable disease

Common cold disease spreads by breathing air containing microbes. Cholera spread by taking infected food or water. AIDS spreads by sharing infected injections, needles with an infected person.

In which of the following human diseases are caused by protozoa?

Female Anopheles mosquito which carries the parasite of malaria. Female Aedes mosquito acts as carrier of dengue virus. Malaria is caused by the protozoan parasite Plasmodium.

Boojho wants to know the preventing method which should not be listed?

Healthcare providers (doctors, nurses, and anyone providing injections) should never reuse a needle or syringe either from one patient to another or to withdraw medicine from a vial. Both needle and syringe must be discarded once they have been used.

Paheli wants to know the method for preventing the occurrence or spread of communicable diseases:

Here, all the statements are correct about the preventing the occurrence or spreading of communicable diseases. Hence, your answer will be option [D].

The disease caused by a protozoan and spread by an insect is

Malaria is the disease which is caused by the spread of a “Protozoan” i.e. “Plasmodium”. It is spread in healthy individuals by the bite of a female “Anopheles Mosquito” caring this “Plasmodium” in their mouth (saliva).

Robert Koch discovered the bacillus anthracis in 1876 which cause Anthrax (a dangerous human and cattle) disease caused by

Bacillus anthracis is an aerobic spore-forming bacterium that causes disease in humans and animals. The bacteria is found in two forms: cutaneous anthrax and inhalation anthrax. Cutaneous anthrax is an infection of the skin caused by direct contact with the bacterium.

Malaria is not caused by a virus or bacteria. Malaria is caused by a parasite known as Plasmodium, which is normally spread through infected mosquitoes. A mosquito takes a blood meal from an infected human, taking in Plasmodia which are in the blood. Ronald Ross is famous for his work concerning malaria and was awarded the Nobel Prize for Physiology or Medicine in 1902. He discovered that the salivary gland in the mosquito was the storage site of malarial parasites and using infected birds, he demonstrated the full life cycle of the malarial parasitic organism

Poliomyelitis is responsible virus for polio. Who discovered polio vaccine?

An inactivated (killed) polio vaccine (IPV) developed by Dr. Jonas Salk and first used in 1955, and. A live attenuated (weakened) oral polio vaccine (OPV) developed by Dr. Albert Sabin and first used in 1961.

Consider the given statements. Choose, which of the following statement is or are correct?

Streptomycin is the antibiotics but hemocyanin is a protein found in mollusks that carries oxygen in much the same way as hemoglobin carries oxygen in human blood. Antibiotics are effective to control disease in plants and animals.

Asthma is a chronic inflammatory disease in lungs. Name the fungus, who is responsible for this?

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterized by an exaggerated response of the immune system (a hypersensitivity response) to the fungus Aspergillus fumigatus.

A disease “Tetanus” is caused by which bacteria:

In 1975 John Bartlett, the discovery of Clostridium difficile and he identified it as the leading cause of hospital-associated infections. Tetanus is caused by a toxin made by spores of bacteria, Clostridium tetani, found in soil, dust and animal feces. When the spores enter a deep flesh wound, they grow into bacteria that can produce a powerful toxin, tetanospasmin. The toxin impairs the nerves that control your muscles (motor neurons).

Class 8 Science Chapter 2 MCQ

Class 8 Science Chapter 2 MCQ (Multiple Choice Questions) of Microorganism: Friend and Foe. There are 25 MCQ Tests containing more than 100 questions with answers and explanation, prepared for new academic session 2020-21.

MCQ are prepared from NCERT Textbook of Class 8 Science and Exemplar book including all the best questions for practice.

Class 8 Science Chapter 2 MCQ for 2020-21

Class: 8	Science
Chapter 2:	MCQ Tests of Microorganism: Friend and Foe

Class 8 Science Chapter 2 MCQ Tests for Exams

Class 8 Science Chapter 2 MCQ Tests of Microorganism: Friend and Foe with complete explanation and answers. All the questions have four option with one option correct. After attempting you can see the answer and explanation for justification. All the important topics of NCERT Books 8th Science Chapter 2 have been added in these MCQs.

Consider the following sentences and choose the correct statements.

[A]. Edward Jenner is known for his role in identification of the causing agent of Anthrax.

[B]. Robert Koch discovered the vaccine for smallpox in 1798.

[C]. Louis Pasteur discovered fermentation in 1857 by demonstrating the microbes cause souring of milk.

[D]. All the above

View Answer

There are some characteristics of tuberculosis patient. Choose the incorrect one:

[A]. Tuberculosis is infectious airborne disease.

[B]. We should avoid standing when the any person cough.

[C]. It is caused by lactobacillus bacteria.

[D]. All the above

View Answer

Pathogenic microorganisms present in host cells are killed by medicines called

[A]. Pain killer

[B]. Antibodies

[C]. Antibiotics

[D]. Vaccines

Paheli is writing some sentences about “algae”. In which of sentences, she is writing as incorrect?

[A]. Spirogyra is single-celled algae.

[B]. Chlamydomonas and diatoms are multi-celled algae.

[C]. Blue-green algae can not fix nitrogen gas of atmosphere.

[D]. All the above.

The two microorganisms which live in symbiotic association in lichens are

[A]. Fungus and protozoa

[B]. Algae and bacteria

[C]. Bacteria and protozoa

[D]. Algae and fungus

View Answer

The gas released during the preparation of bread is

[A]. Oxygen

[B]. Carbon dioxide

[C]. Nitrogen

[D]. Sulphur dioxide

View Answer

Malaria is caused by

[A]. Bacteria

[B]. Virus

[C]. Fungus

[D]. None of the above.

There are given some statements. Boojho wants to know which of the following statement is or are incorrect?

[A]. Housefly carries the disease-causing microbes’ insides the body.

[B]. Mosquito carries microbes outside its body.

[C]. Ades mosquito carries the plasmodium parasite of malaria.

[D]. All the above

The precaution is observed in the use of antibiotics. Choose the incorrect sentence(s):

[A]. Antibiotic may kill the useful bacteria in the body and harm us.

[B]. Wrong dose of antibiotics makes the antibiotic less effective.

[C]. Antibiotics should be taken only on the advice of perfect doctor.

[D]. None of the above

View Answer

Q10

Paheli and boojho discussed a topic of microorganisms. Choose which of the following statements is or are incorrect?

[A]. A dilute solution of Acetic acid is called vinegar.

[B]. Acetobacter bacteria convert alcohol into acetic acid.

[C]. Yeast is capable of converting sugar into alcohol.

[D]. None of the above.

View Answer

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Types of Fungi

Yeasts:	Unicellular organisms.
Moulds:	Multi cellular organisms.
Mushrooms:	Multi cellular organisms.
Maldews:	Unicellular organisms.

The Common Characters of Viruses

They are the smallest living organisms.
They do not have a cellular structure.
They have a simple structure, consisting of a small piece of Nucleic Acid (either DNA or RNA), surrounded by a protein coat.
They are on the boundary between living and non-living.

Discovery of Viruses

In 1852, a Russian botanist D.I. Ivanovsky discovered viruses from tobacco plants. These viruses were named as TMV (Tabacco Mosaic Viruses). Viruses are the smallest living organisms, ranging in size from about 20-300 mm on average. They cannot be seen with the simple microscope. They pass through filters which retain bacteria.

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What is micro-biology?

There is a world of living organisms which cannot be seen with the naked eyes. They can be seen only through a microscope. Microorganisms are often described as single -celled or unicellular organisms, but there are certain species that are multi-cellulars. The study of micro-organisms is called micro-biology.

What are Extremophiles?

Micro-organisms are found in a variety of places, and they can survive in extremely harsh environmental
conditions. Some types of micro-organisms have adapted to the extreme conditions and sustained colonies; these organisms are known as Extremophiles.

What is Bacteriology?

Becteria are microscopic, unicellualar organisms. They are often coocus -(Spherical) or red-shaped and 0.5- 51/m in the longest dimension. The study of bacteria is known as Bacteriology.

What are Pathogens?

Some micro-organisms are useful to us in many ways, while some are definitely harmful since they cause diseases. The microorganisms which cause disease are known as Pathogens.

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Class 8 Science Chapter 2 MCQ

Class 8 Science Chapter 2 MCQ for 2020-21

Class 8 Science Chapter 2 MCQ Tests for Exams

Consider the following sentences and choose the correct statements.

There are some characteristics of tuberculosis patient. Choose the incorrect one:

Pathogenic microorganisms present in host cells are killed by medicines called

Paheli is writing some sentences about “algae”. In which of sentences, she is writing as incorrect?

The two microorganisms which live in symbiotic association in lichens are

The gas released during the preparation of bread is

Malaria is caused by

There are given some statements. Boojho wants to know which of the following statement is or are incorrect?

The precaution is observed in the use of antibiotics. Choose the incorrect sentence(s):

Paheli and boojho discussed a topic of microorganisms. Choose which of the following statements is or are incorrect?

Types of Fungi

The Common Characters of Viruses

Discovery of Viruses

What is micro-biology?

What are Extremophiles?

What is Bacteriology?

What are Pathogens?

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