SSC Worksheet for Chapter - 3 Microorganisms: Friend and Foe Class 8
Worksheets For class 8
Find SSC Worksheet for chapter-3 Microorganisms: Friend and Foe class 8
- BOARD: SSC
- BIOLOGY Worksheet -3
- TOPIC: Microorganisms Friend and Foe
- For otherSCC Worksheet for class 8 Science check out main page of Physics Wallah.
Fill in the blanks:
- Cholera is caused by ___________.
- Blue green algae fix ___________ directly from air to enhance fertility of soil.
Viruses can reproduce in
- Plants and animals
Tuberculosis is caused by
- Blue green algae
Carrier for dengue fever is
- Anopheles mosquito
- Aedes mosquito
The most common carrier of communicable diseases is
Match the organisms in Column A with their action in Column B:
- Bacteria (a) Fixing nitrogen
- Rhizobium (b) Setting of curd
- Lactobacillus (c) Baking of bread
- Yeast (d) Causing malaria
- A protozoan (e) Causing cholera
- A virus (f) Causing AIDS
- Producing antibodies
- How can we prevent mosquitoes from breeding?
- Name the microorganisms which can fix atmospheric nitrogen in the soil.
- What are preservatives? Name two common preservatives used to preserve jams and pickles.
- Write a short paragraph on the harms caused by microorganisms.
Solutions: to worksheet-3 Topic- Microorganisms Friend and Foe
- Bacteria Vibrio cholerae
- (d) Plants and animals
- (d) Bacteria
- (c) Aedes mosquito
- (b) Housefly
Mosquitoes can be prevented from breeding by using the following ways:
- Do not allow water to stagnate in your surroundings
- Keep your surroundings neat and clean
- Use mosquito repellant
- Rhizobium, Nitrobacter, Azotobacter are the microorganisms which fix atmospheric nitrogen into the soil.
- Preservatives are the substances added to the food in order to maintain its taste and quality for a longer period of time. Sugar is commonly added to preserve jams, and oil and salt is added to preserve pickle.
Micro-organisms causing diseases in plants, animals and humans are termed as pathogens. The harms caused by these microbes are as follows:
- Bacteria like Vibrio cholerae and Salmonella typhi causes disease like cholera and typhoid respectively.
- Also diseases like pneumonia and tuberculosis is caused by bacteria Streptococcus pneumonae and Mycobacterium species.
- Female Anopheles mosquito is a carries for malarial parasite Plasmodium and female Aedes mosquito carries dengue virus causing dengue fever.
- Bacillus anthracis causes anthrax which a dangerous disease for humans as well as cattles.
- Canker is caused in citrus fruits due to bacteria.
- Yellow vein mosaic disease is caused in okra (bhindi) by virus transmitted through insect.
- Serious diseases caused by viruses are chicken pox, jaundice, AIDS. SARS, Herpes, swine flu, mumps, polio etc.
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