NCERT Class 7 Science Chapter 1 Nutrition In Plants Important Questions

Here are important questions that could be asked from NCERT Class 7 Science Chapter 1 Nutrition in Plants.

1. What are the main components of food?

Carbohydrates, proteins, fats, vitamins and minerals are the main components of food.

2. What are nutrients?

Nutrients are essential components like carbohydrates, proteins, fats, vitamins and minerals present in food. They are essential for the growth and sustenance of our body.

3. Directly or indirectly all animals including humans are dependent on plants. Why?

Plants can prepare their own food. However, animals cannot do so. They obtain food from plants or other animals that eat plants. Hence, all animals are dependent on plants for food.

4. How do plants prepare their own food?

Plants prepare their food from water, carbon dioxide and minerals in the presence of sunlight.

5. What is autotrophic nutrition?

The mode of nutrition in which organisms prepare their own food from simple substances is called autotrophic nutrition. Since plants prepare their own food, they are called autotrophs.

6. What is heterotrophic nutrition?

The mode of nutrition in which animals and other living organisms consume food prepared by plants is called heterotrophic nutrition. All animals are heterotrophs because they depend on plants for food.

7. How do plants make their own food?

Plants prepare food in their leaves. Roots absorb water and other minerals from the soil. Vessels which run like pipes throughout the roots, stem, branches and leaves of plants take water and minerals to the leaves. Leaves have a green pigment called chlorophyll. Chlorophyll helps plants to capture the energy of sunlight. Using this energy, plants prepare food from carbon dioxide and water in the presence of sunlight. This process is called photosynthesis.

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8. Why is sun the ultimate source of energy for all living organisms?

Plants require sunlight for preparing food. The leaves of plants have a special pigment called chlorophyll to capture the energy of sunlight. Since all other living organisms depend on plants for food, the sun which enables plants to prepare food is the ultimate source of energy for all living organisms.

9. What is photosynthesis?

Photosynthesis is the process by which plants prepare their own food. In the presence of sunlight, leaves prepare carbohydrates from carbon dioxide and water. This process also releases oxygen.

10. How do plants with red and brown leaves prepare food?

Red and brown leaves also have the green pigment chlorophyll. Since these leaves have large amounts of red and other pigments, the green colour is not visible. However, chlorophyll is still present in them.

11. Why do plants need nitrogen?

Plants prepare carbohydrates during photosynthesis. Carbohydrates are made up of carbon, hydrogen and oxygen. Plants also prepare protein and fats. Proteins contain nitrogen and hence plants require nitrogen to make protein. Plants cannot absorb the gaseous nitrogen present in the atmosphere. Hence, they depend on soil bacteria which can convert gaseous nitrogen into a form that plants can use. Plants absorb this nitrogen along with water from soil. With the help of this nitrogen, plants synthesise proteins and vitamins.

12. What are insectivorous plants?

Plants which eat insects are called insectivorous plants.

13. What is saprotrophic nutrition?

The mode of nutrition in which organisms absorb nutrients from dead and decaying matter is called saprotrophic nutrition.

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14. What is symbiosis?

Symbiosis is the relationship between organisms which live together and depend on each other for shelter and nutrients. An example of this is the relation between some plants and the fungi living inside their roots.

15. What are lichens?

Lichens are organisms that involve a symbiotic relationship between an alga and a fungus. The fungus provides shelter, water and minerals to the alga whereas the alga which has chlorophyll prepares the food for fungus.

16. Why it is important to add fertilisers to the soil?

Plants keep on absorbing minerals and nutrients from the soil. As a result, the amount of nutrients present in the soil declines. It is important to enrich the soil from time to time adding fertilizers and manure to it.

17. Why does Rhizobium live in the roots of gram, and peas? / Explain the symbiotic relationship between Rhizobium and peas.

Rhizobium can absorb atmospheric nitrogen and convert it into a form that plants can use. Hence, it is highly useful to plants. However, Rhizobium cannot prepare its own food. Hence, it lives in the roots of legumes and provides them with nitrogen. In return, the plants provide the bacteria with food and shelter.

18. What are parasites?

Parasites are plants which depend on food produced by other plants. An example of this is the cuscuta plant which absorbs readymade food the plant on which it is climbing.

True or False

1. Photosynthesis can only take place in leaves

2. Carbon dioxide is produced during photosynthesis.

3. Only green leaves can perform photosynthesis.

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4. Parasites use autotrophic mode of nutrition.

5. Green stems can perform photosynthesis.

Answers

1. false; 2. False; 3. False; 4. False; 5. true

Fill in the blanks

1. …………………………….. can synthesise food for themselves.

2. All living organisms require ………………………

3. Animals use …………………………….. nutrition.

4. Plants use …………………………. nutrition.

5. ………………………… are the food factories of plants.

6. ………………………… are the tiny pores present on the surface of leaves.

7. All living organisms are made of ………………………….

8. …………………………. is the centrally located, spherical structure inside a cell.

9. The jelly like substance that surrounds nucleus is called …………………………

10. The thin outer wall of a cell is called …………………………………

11. Algae are ……………………………. In colour.

12. Carbohydrates are made up of ……………., ………………………, …………………

13. Plants that do not have chlorophyll depend on …………………………….. nutrition.

14. The bacteria ……………………… can absorb atmospheric nitrogen and convert it into a form that plants can use.

Answers

1. Plants, 2. food, 3. heterotrophic, 4. autotrophic, 5. leaves, 6. stomata, 7. cells, 8. nucleus, 9. cytoplasm, 10. cell membrane, 11. green, 12. carbon, hydrogen and oxygen, 13. heterotrophic nutrition, 14. Rhizobium

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