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2. How will you test a leaf for starch? Mention any precautions you will take.
3. How do plants get nitrogen to synthesize proteins?
4. All animals—whether herbivores, carnivores or omnivores-depend on plants for their food.
Discuss.
5. Explain the following with the help of an example for each:
Answers
Answer:
2.Step 1: A fresh leaf is taken. Step 2: The leaf is boiled in water for few minutes to soften the cells in the leaf. Step 3: Now, dip this leaf in iodine solution. Step 4: The color of the leaf will changes into blue black color when iodine is added to it which shows the presence of starch in it.
3.Plants can get nitrogen to synthesise protein by- 1) They modify some parts of their body such as apex of leaf and change themselves to become insectivorous plants. 2) Leguminous plants like- pea plants,etc. have rhisobium bacteria in their root nodules which also provide them nitrogen.
4.All animals whether herbivores, carnivores or omnivores can not make their own food; hence, they depend on the plants for their food. Herbivores feed on plants to obtain nutrition. Again, the carnivores eat herbivores to obtain nutrition. Thus, carnivores indirectly depend on plants for their food.
5.The organisms having holozoic nutrition are further classified in three categories. These are:
•Carnivores
•Herbivores
•Omnivores
•Carnivores
The organisms which eat other animals or meat only are called carnivores. For example, lion, bear, snake, crocodile, lizard, eagle and wolf etc.
•Herbivores
The organisms which consume or eat only plants as their source of food are called herbivores. For example, cow, rabbit, goat, deer, locust and camel etc.
•Omnivores
The organisms which eat both plant food as well as meat of animals are called omnivores. The best examples of omnivores are human beings, crow, dog, sparrow and ants etc.