Nutrition, Transportation, Respiration and Excretion

MODULE - 5
The Living World
Notes
Life Processes-1 Nutrition, Transportation, Respiration and Excretion
(iii) Saprotrophic nutrition: You must have seen a white cottony growth
developing on your wet leather shoes or belts especially when they get wet during
rainy days. This is a fungus. The fungus grows and feeds on substances, which
were once part of the living organisms, such as stored food, wood, leather and
rotten plant products. Some common examples are mushrooms, bread mould,
yeast, etc. Organisms that derive their food from dead and decaying organisms
are called saprotrophs. Saprotrophs help in cleaning the environment by
decomposing the dead and decaying organic matter.
INTEXT QUESTIONS 22.1
1. Give two examples of autotrophs. Why do you call them so?
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2. Why are autotrophs termed ‘producers’ of food chain?
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3. Fill in the blanks in the flow chart given below:
Types of Nutrition
4. The parasitic and saprotrophic modes of nutrition do not need the three processes
required by holozoic animals. Which processes are these?
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5. Classify the following as saprotrophs or parasites: leech, yeast, head louse,
mushroom
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22.3 NUTRITION IN PLANTS—PHOTOSYNTHESIS
(Photo :light; synthesis : make)
Photosynthesis is ‘a biochemical process by which green plants manufacture their own
food using carbon dioxide and water as raw materials in the presence of sunlight and
chlorophyll’. Oxygen is released as a by-product in this process.
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SCIENCE AND TECHNOLOGY