Life Processes Notes

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Life Processes Part 1 :
Q1.Distinguish between autotrophic and heterotrophic nutrition with examples Autotrophic Nutrition| Heterotrophic Nutrition|
The mode of nutrition in which organisms can prepare their own food, using raw materials water and carbon dioxide, in the presence of sunlight and chlorophyll| It is the mode of nutrition in which organisms cannot prepare food on their own and thus depend on autotrophs for food.| Eg : All green plants, blue green algae| Eg : man, fungi, horse|

Q2.Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans? Ans – In multicellular organisms, there are millions of cells. These cells are not in direct contact with the environment, hence simple diffusion from cell to cell cannot meet the requirement of all the body cells. Q3.What are the four essential requirements for photosynthesis. Also mention the source of each of these. Ans – 1)Carbon dioxide (from atmosphere)

2)Water (from the soil – absorbed by root hairs)
3)Sunlight (from the sun)
4)Chlorophyll (present in the chloroplast in green parts of the plant) Q4.Why in single cell organisms (like amoeba, etc) specific organs for taking food, exchange of gases, etc. are not required? Ans – This is because there is only one cell. The entire surface of the organism is in contact with the environment and simple cell – cell diffusion can meet all the requirement. Q5.What are the three types of heterotrophic nutrition?

Ans – 1)Parasitic nutrition – The mode of heterotrophic nutrition in which the organism (parasite) obtains nutrition from another organism (host) either from its surface or by entering its body. 2)Saprophytic nutrition – The mode of heterotrophic nutrition in which the organism (saprophyte) feeds on dead and decaying organic matter. Eg : fungi 3)Holozoic nutrition – The mode of heterotrophic nutrition in which the organism feeds on solid food, (can even be the whole organism). Eg : man, dog...
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