M.M: 73 marks Date: 15/08/2011
Monday, August 15, 2011
Science Class 8 Model Test Paper From Chapter 2 - Microorganisms - Friends Or Foe
M.M: 73 marks Date: 15/08/2011
Time: 1 hour
Q 1: Fill in the blanks (1 mark each per question x 31 = 31 marks)
- Those organisms which are too small to be seen without a _________ are called micro-organisms.
- As a result of ________ cycle, the percentage of nitrogen in the atmosphere remains more or less constant.
- Our Earth’s atmosphere has ________ percent of nitrogen gas.
- The process of converting nitrogen gas of atmosphere into compounds of nitrogen, which can be used by plants is called ______________ _____________
- Two examples of leguminous plants are ______ and ______
- The circulation of nitrogen element through living things and non living environment such as air, soil and water is called __________ _______ in nature.
- _________ bacteria can convert nitrogen gas or air into nitrogen compounds.
- The food material which is preserved by pasteurisation is _________
- Common salt has been used to preserve ________ and _______ for ages.
- ________ ____________ method is nowadays used for preservation of foods like meat, fish and their products – food and vegetables.
- Pasteurisation method is based on the name of French scientist ________ _________
- ____________ _______ and ______ are still widely used as preservatives for the preservation of fruits and vegetables in the form of pickles.
- The three special chemicals which are used for preservation of food are _________ __________, _______ ___________ and _______ ________.
- The process in which the food materials are given suitable physical or chemical treatment to prevent them from getting spoilt is called ___________ _______________.
- Cholera is caused by ___________
- The most common disease that spreads by mosquitoes is _____________
- ________________ causes malaria disease.
- _________ _________ mosquito carries the parasite of malaria.
- Another disease that spreads by mosquitoes is ___________.
- Two dangerous diseases caused by housefly are _________ and ______________.
- Two plant diseases caused by micro-organisms are _______________________ and __________________. (more than one word can come in a single blank).
- _________ is produced with the help of yeast.
- ________ _______ discovered the vaccine for smallpox in 1798.
- Two materials that cannot be decomposed by micro-organisms are _______ and _______.
- _____________ bacteria promote the formation of curd from milk.
- _____________ ___________ discovered Penicillin.
- The process of conversion of ______ into _______ by the action of yeast is called fermentation.
- _______ is the micro-organism used in making bread, cakes and pastries.
- _______ are the micro-organisms which reproduce only inside the living cells of other organisms.
- Full form of HIV is __________ ________________ ______________
- AIDS stand for __________ ___________ ____________ _________________
Q 2: Complete the following table showing some common human diseases by filling the causative micro-organism, mode of transmission and one general preventive measure.
(3 marks x 4 = 12 marks)
Human disease | Causative micro-organism | Mode of transmission | General Preventive Measure |
Polio | |||
Typhoid | |||
Cholera | |||
Hepatitis B |
Q 3: In brief, write about pasteurisation. (2 marks)
Q 4: What do you understand by food poisoning? What are its two major symptoms? (3 marks)
Q 5: Write one reason behind sugar being used as a preservative? (1 mark)
Q 6: Write names of two diseases that are caused in animals by micro-organisms. Also write the type of micro-organism that causes the respective disease. (4 marks)
Q 7: Which type of micro-organism causes Dengue? Write the carrier of dengue disease. (2 marks)
Q 8: What do you understand by communicable diseases? Write names of two such diseases. (3 marks)
Q 9: Explain in brief, how micro-organisms helps in keeping the environment clean? (2 marks)
Q 10: What do you understand by a vaccine? Write names of four diseases that can be prevented by vaccination at the right time. (3 marks)
Q 11: Define antibiotic. Write two examples of the same. (3 marks)
Q 12: Why is curd added to idlis and bhaturas? (1 mark)
Q 13: Write short note on Protozoa and Fungi. Give two examples of each. Make diagram of one type of protozoa and one type of fungi. (6 marks)
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