NCERT Class 7 Chapter 1 Nutrition in Plants Paheli Boojho Answer
1. Boojho wants to know how plants prepare their food?
Green leaves of a plant contain a green colour pigment called ‘chlorophyll’. Plants absorb carbon dioxide, water and minerals from the surrounding, and the chlorophyll uses the energy of the sunlight to convert atmospheric carbon dioxide into glucose. Glucose serves as food for the plant. We call this process “photosynthesis”.
2. Paheli wants to know why our body can not make food from carbon dioxide, water and minerals like plants do?
Our body does not contain chlorophyll. Chlorophyll is necessary to convert carbon dioxide and water into food. As a result, we depend on other food sources like food produced by the plants.
3. Bujho wants to know how water and minerals absorbed by roots reaches leaves?
Roots of a plant absorb water and minerals from the soil. The root contains tube-like vessels which connect the root to leaves. We call these vessels as xylem. Xylem carries water and minerals from the root and transports it to the leaves.
4. Paheli wants to know what is so special about the leaves that they can synthesise food but other parts of the plant cannot?
Leaves of a plant contain a green colour pigment called Chlorophyll. These green coloured pigment utilises the energy of the sunlight and converts carbon dioxide and water into food. Other parts of the plant do not have chlorophyll, so they can not produce foods.
Some plants like cactus have adapted to do photosynthesis through their stem. These are some of the exceptions.
5. Boojho has observed some plants with deep red, violet and brown leaves. He wants to know whether these leaves also carry out photosynthesis.
Some plant has colourful leaves. It happens because they contain other colour pigments. But this does not mean that they do not contain chlorophyll. They have chlorophylls in their leaves, but other pigments mask the green colour of chlorophyll. As a result, we do not see a green appearance, but these leave do photosynthesis just like typical plants.
6. Paheli wants to know whether mosquitos, bed bugs, lice and leeches that suck our blood are also parasites.
A parasite is an unwelcomed guest which exploits the host. For example, the Cuscuta ‘amarbel’ leaves on other plant and deprives the host of its nutrition. Similarly, musquitos and bed bucks suck our blood and take away our blood. Hence they are also parasites.
7. Boojho is confused. If the pitcher plant is green and carries out photosynthesis, then why does it feed on insets?
Pitcher plants have jug like apparatus. This apparatus attracts small insects. Insects come near pitcher and are trapped into it. We call such type of plants an “insectivorous plant“. These plants carry photosynthesis like usual plants, but it lacks nitrogen and other minerals. Small insects contain a large number of nitrogenous substances and minerals. By digesting them, these insectivorous plants fill their nitrogen requirement.
8. Boojho sees some mushrooms. They do not have a mouth like animals. They are also not green like plants. Then how they obtain their nutrition?
Mushrooms grow on decaying material. They obtain their nutrition these decaying materials. We call such an organism a Saprophytes. They are necessary for us because they clean the earth from dead materials.
9. Paheli is keen to know whether her beautiful shoes, which she wore on special occasions, were spoiled by the fungi during the rainy season. She wants to understand how fungi appear suddenly during the rainy season.
Fungal spores are present in the air. They sit on dead materials and start growing. Moisture and warm condition favours them. In rainy season humidity is high. As a result, fungi quickly grow on dead leather and spoil it. To prevent it, we should keep our shoes in a closed box.
10. Boojho says once his grandparent told him that a fungus spoiled his wheat fields. He wants to know if fungi cause diseases also.
Most fungi are harmless and clean our earth. Some fungi are also useful to us. For example, we use yeast to make bread; some mushrooms are edible, they provide us with proper nutrition, vitamin D and minerals. Some fungi also produce antibiotics. We use such antibiotics as medicine to prevent diseases. But some fungi also cause diseases in plants and animals. Wheat rust is a common fungal disease which reduces the crop yield. With the proper use of medicines, these harmful fungi can be easily eliminated.