Test: Microorganisms Friend And Foe - 3


20 Questions MCQ Test Science Class 8 | Test: Microorganisms Friend And Foe - 3


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This mock test of Test: Microorganisms Friend And Foe - 3 for Class 8 helps you for every Class 8 entrance exam. This contains 20 Multiple Choice Questions for Class 8 Test: Microorganisms Friend And Foe - 3 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Microorganisms Friend And Foe - 3 quiz give you a good mix of easy questions and tough questions. Class 8 students definitely take this Test: Microorganisms Friend And Foe - 3 exercise for a better result in the exam. You can find other Test: Microorganisms Friend And Foe - 3 extra questions, long questions & short questions for Class 8 on EduRev as well by searching above.
QUESTION: 1

Which of the following is the smallest microorganism?

Solution:

A virus is in the average smaller than a bacteria and unicellular algae are more or less in the same size domain as bacteria but more commonly algae are multicellular and hence larger.

QUESTION: 2

Identify W, X and Y?

Solution:

In the given figure W - virus, X - fungus and Y - protozoan.

QUESTION: 3

Identify bacteriophage.

Solution:

A bacteriophage  also known informally as a phage is a virus that infects and replicates within bacteria and archaea. Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate.

QUESTION: 4

Which of the following statements describes bacteriophage correctly?

Solution:

Bacteriophage is a type of virus which attacks bacteria.

QUESTION: 5

Fungi reproduces by

Solution:

Fungi reproduces by spore formation.

QUESTION: 6

Which one of the following is called pond silk?

Solution:

Spirogyra is called pond silk.

QUESTION: 7

The moist bread becomes mouldy after a few days when it is left in a container with a cover. Which of the following conditions favour the growth of the fungus?

Solution:

If a piece of bread is kept in a container in a moist place for two to three days, some light type of hairy growth may happen on the surface. It is generally referred to as the bread mold. It is a kind of fungus. The absence of light and moist temperature favour the growth of the fungus.

QUESTION: 8

Which of the following microorganisms play an important role in maintaining the balance of nitrogen gas in the atmosphere?

Solution:

➡️ Rhibozium is the bacteria which play an important role in mainting the balance of nitrogen gas in atmosphere.
➡️ This bacteria shows Symbosis relationship.
➡️ The bacteria like Azatobacter , Nosac etc... shows nitrogen fixation in atmosphere.
➡️ They provide Nitrogen to plants. which is an essential element of plants.

QUESTION: 9

What causes the dough to rise when yeast is added to it?

Solution:

The release of carbon dioxide gas causes dough to rise when yeast is added to it. (Fermentation)

QUESTION: 10

What process takes place when yeast is added to grape juice and left for a week?

Solution:

Fermentation takes place when yeast is added to grape juice and left for a week.

QUESTION: 11

Which of the following enzymes is secreted by bacteria that can digest cellulose?

Solution:

Cellulase is secreted by bacteria that can digest cellulose.

QUESTION: 12

Which of the following is/are the functions performed by the microorganisms in the field of biotechnology?

Solution:

The production of hormones and gene therapy through micro- organism is taken up in the field of biotechnology.

QUESTION: 13

Which of the following is/are produced by using bacteria?

Solution:

Antibiotics cheese and yoghurt are produced by bacteria.

QUESTION: 14

Which of the following terms is given to the microorganisms that cause diseases?

Solution:

Most microbes belong to four major groups: bacteria, viruses, protozoa or fungi. A few harmful microbes, for example less than 1% of bacteria, can invade our body (the host) and make us ill. Microbes cause infectious diseases such as flu and measles.

There is also strong evidence that microbes may contribute to many non–infectious chronic diseases such as some forms of cancer and coronary heart disease. Different diseases are caused by different types of microorganisms. Microbes that cause disease are called pathogens.Disease-causing microbes can also be called pathogens, germs or bugs and are responsible for causing infectious diseases.

QUESTION: 15

Which of the following disease causing pathogens is / are carried by mosquitoes?

Solution:

Pathogens causing Dengue fever and malaria are carried by mosquitoes.

QUESTION: 16

Identify the disease that is caused by protozoa.

Solution:

The disease is malaria.

QUESTION: 17

Which of the following options is/are true about the diseases, microorganisms which cause them and the symptoms of the diseases?

Solution:

Options (i) and (ii) are true about the microorganisms the diseases they cause and the symptoms.

i) Malaria is a life-threatening disease. It's typically transmitted through the bite of an infected Anopheles mosquito. Infected mosquitoes carry the Plasmodium parasite.

Symptoms of malaria can develop as quickly as 7 days after you're bitten by an infected mosquito.

  • high temperature of 38C or above.
  • feeling hot and shivery.
  • headaches.
  • vomiting.
  • muscle pains.
  • diarrhoea.
  • generally feeling unwell.

ii) Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). It is a major global health problem. It can cause chronic infection and puts people at high risk of death from cirrhosis and liver cancer

Common symptoms of hepatitis B infection

  • Feverfatigue, muscle or joint pain.
  • Loss of appetite.
  • Mild nausea and vomiting.
  • Stomach pain.
  • Pale or light colored stools.
  • Dark, tea colored urine.
QUESTION: 18

Which of the following can affectively prevent the ringworm disease?

Solution:

Improving personal hygiene prevents ringworm disease because ringworm is a fungal infection so doesn't treated by vaccine or anti bacterial medicine.

QUESTION: 19

Which of the following bacteria lives symbiotically in pea plants?

Solution:

Rhizobium bacteria live symbiotically.

QUESTION: 20

Which of the following bacteria causes Cholera?

Solution:

Vibrio causes cholera.

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