Extra Questions for Class 7 Science Chapter 1 Nutrition in Plants
Extra questions for Class 7 Science Chapter 1 Nutrition in Plants with answers is given below. Our subject expert prepared these solutions as per the latest NCERT textbook. These questions will be helpful to revise the all topics and concepts. CBSE Class 7 extra questions are the most simple and conceptual questions that are prepared by subject experts for the students to study well for the final exams. By solving these extra questions, students can be very efficient in their exam preparations.
Nutrition in Plants Class 7 Science Extra Questions and Answers
Very Short Extra Questions and Answer
1. Define parasites.
Answer: Parasites they are those organisms which grow on other plants or animals for their food, e.g. Cuscuta.
2. Name the bacteria that can fix atmospheric nitrogen.
Answer: Rhizobium is the bacterium which can fix atmospheric nitrogen.
3. Name a parasitic plant with yellow, slender and tubular stem.
Answer: Cuscuta
4. Give one example of parasite.
Answer: Amarbel
5. Name one plant that traps and feeds on insects.
Answer: Pitcher Plant
6. Name a plant that has both autotrophic and heterotrophic mode of nutrition.
Answer: Insectivorous Plant
7. What are fluffy umbrella-like patches growing on rotting wood during the rainy season called?
Answer: These organisms are called fungi.
8. How can cells be seen?
Answer: Most type of cells can be seen only under the microscope.
9. Where is nucleus located in a cell?
Answer: In most of the cell, nucleus is centrally located.
10. What are carbohydrates made up of?
Answer: The carbohydrates are made of carbon, hydrogen and oxygen.
11. From where do plants get raw materials to prepare their food?
Answer: Plants get raw materials to prepare their food from their surroundings.
12. Where does the synthesis of food in a plant usually take place?
Answer: The synthesis of food in plants occurs in leaves.
13. What is the ultimate source of energy for all living organisms?
Answer: Sun is the ultimate source of energy for all living organisms.
14. Why do some plants feed on insects?
Answer: Insectivorous plants grow in soil which lack nitrogen, therefore they eat insects to fulfill their need of nitrogen.
15. What are the components of food?
Answer: Carbohydrates, proteins, fats, vitamins and minerals are components of food.
Short Extra Questions and Answers
1. What are insectivorous plants?
Answer: Insect-eating plants such as pitcher plant are called insectivorous plants.
2. What do you mean by nutrition?
Answer: Nutrition is the mode of taking food by an organism and its utilization by the body.
3. Why photosynthesis is named so?
Answer: Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis (Photo: light; synthesis: to combine).
4. What are heterotrophs?
Answer: Animals and most other organisms take in ready-made food prepared by the plants. They are called heterotrophs (heteros = other).
5. What are stomata?
Answer: Tiny pores are present on the surface of the leaves which helps in exchange of gases. Such pores are called stomata.
6. What are called autotrophs?
Answer: Organisms able to make food themselves from simple substances are called autotrophs.
7. What is heterotrophic nutrition?
Answer: Heterotrophic nutrition is the mode of nutrition in which organisms depend upon other organisms to survive.
8. What are nutrients?
Answer: Carbohydrates, proteins, fats, vitamins and minerals are components of food. These components of food are called nutrients.
9. What is chlorophyll?
Answer: A green pigment present in all green plants which helps leaves to capture the energy of the sunlight is called chlorophyll.
10. Where and in what conditions do fungi grow?
Answer: Fungi grow on pickles, leather, clothes and other articles that are left in hot and humid weather for long time.
11. How do fungi grow and develop?
Answer: The fungal spores are generally present in the air. When they land on wet and warm things they germinate and grow.
12. Why algae are green in colour?
Answer: They contain chlorophyll which gives them the green colour. Algae can also prepare their own food by photosynthesis.
13. What are the raw materials required for photosynthesis?
Answer: Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of photosynthesis.
14. Do insectivorous plants perform photosynthesis?
Answer: Insectivorous plants got leaves therefore they can photosynthesis, which means they can prepare their food in the presence of sunlight.
15. What are algae?
Answer: We often see slimy, green patches in ponds or in other stagnant water bodies. These are generally formed by the growth of organisms called algae.
16. Why do organisms need to take food?
Answer: The food enables living organisms to build their bodies, to grow, to repair damaged parts of their bodies and provide the energy to carry out life processes.
17. Why plants such as pitcher plant do not get all the required nutrients from the soil in which they grow?
Answer: Plants such as pitcher plant do not get all the required nutrients from the soil in which they grow because they are deficient in nutrients such as nitrogen.
18. What is Cuscuta?
Answer: Cuscuta is a parasitic plant. It is yellow tubular structures twining around the stem and branches. It does not have chlorophyll. It takes readymade food from the plant on which it is climbing.
19. What is the role of rhizobium bacteria in leguminous plant?
Answer: The bacterium called Rhizobium present in leguminous plant can take atmospheric nitrogen and convert it into a soluble form. Thus help in nitrogen fixation.
20. Some plants have deep red, violet or brown leaves. Do these leaves also carry out photosynthesis?
Answer: The leaves other than green also have chlorophyll. The large amount of red, brown and other pigments mask the green colour. Photosynthesis takes place in these leaves also.
21. What is so special about the leaves that they can synthesis food but other parts of the plant cannot?
Answer: The leaves have a green pigment called chlorophyll. It helps leaves to capture the energy of the sunlight. This energy is used to synthesis (prepare) food from carbon dioxide and water.
Long Extra Questions and Answers
1. How would you test the presence of starch in leaves?
Answer: Iodine solution is used to test leaves for the presence of starch.
Test – Remove chlorophyll by boiling it in alcohol and then add 2 drops of iodine solution. If the color changes to blue, indicates the presence of starch in the leaves.
2. How do plants obtain the raw materials from the surroundings?
Answer: Water and minerals present in the soil are absorbed by the roots. Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. The leaves have a green pigment called chlorophyll. It helps leaves to capture the energy of the sunlight.
3. Explain the mode of nutrition in fungi.
Answer: They secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it. This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition.
4. If the pitcher plant is green and carries out photosynthesis, then why does it feed on insects?
Answer: These plants grow in soil that is deficient in nitrogen. All living things must have nitrogen. These plants (e.g. pitcher plant) are green and carry out photosynthesis to obtain a part of the food required by them. So, they feed on insects to obtain the nitrogen needed for their growth.
5. How farmer is benefited from symbiotic relationship between rhizobium bacteria and legumes?
Answer: This association is of great significance for the farmers. The bacterium called Rhizobium present in leguminous plant can take atmospheric nitrogen and convert it into a soluble form. So, they do not need to add nitrogen fertiliser to the soil in which leguminous plants are grown.
6. How do plants transport raw materials to the food factories of the plants?
Answer: Water and minerals are transported to the leaves by the vessels which run like pipes throughout the root, the stem, the branches and the leaves. They form a continuous path or passage for the nutrients to reach the leaf. The leaves have a green pigment called chlorophyll. It helps leaves to capture the energy of the sunlight.
7. From where do the plants obtain nitrogen?
Answer: Nitrogen is present in abundance in gaseous form in the air.
However, plants cannot absorb nitrogen in this form. Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. These soluble forms are absorbed by the plants along with water. Farmers add fertilisers rich in nitrogen to the soil.
8. Can we say that the insectivorous plants are partial heterotrophs?
Answer: These plants grow in soil that is deficient in nitrogen. All living things must have nitrogen. These plants are green and carry out photosynthesis to obtain a part of the food required by them. They feed on insects to obtain the nitrogen needed for their growth. So, we can say that the insectivorous plants are partial heterotrophs.
9. Explain symbiotic relationship in rhizobium and leguminous plants.
Answer: The bacterium called Rhizobium can take atmospheric nitrogen and convert it into a soluble form. But Rhizobium cannot make its own food. So it lives in the roots of gram, peas, moong, beans and other legumes and provides them with nitrogen. In return, the plants provide food and shelter to the bacteria. They, thus, have a symbiotic relationship.
10. Give a brief description of the process of synthesis of food in green plants?
Answer: The synthesis of food in plants occurs in leaves. Therefore, all the raw materials must reach there. Water and minerals present in the soil are absorbed by the roots and transported to the leaves. Carbon dioxide from air is taken in through stomata present on the surface of the leaves. Chlorophyll helps leaves to capture the energy of the sunlight. This energy is used to synthesis (prepare) food from carbon dioxide and water.
11. Explain symbiotic relationship with the help of example.
Answer: Some organisms live together and share shelter and nutrients. This is called symbiotic relationship. For example, in organisms called lichens, a chlorophyll-containing partner, which is an alga, and a fungus live together. The fungus provides shelter, water and minerals to the alga and, in return, the alga provides food which it prepares by photosynthesis.
12. Define cells, cell membrane, nucleus and cytoplasm.
Answer: Cells – the bodies of living organisms are made of tiny units called cells.
Cell membrane – The cell is enclosed by a thin outer boundary, called the cell membrane.
Nucleus – Most cells have a distinct, centrally located spherical structure called the nucleus.
Cytoplasm – The nucleus is surrounded by a jelly-like substance called cytoplasm.
13. Distinguish between a parasite and a saprotroph.
Answer:
| Parasite | Saprotroph |
| 1. They live in or on another organism (its host) and get their nutrients from that host. | 1. They secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it. |
| 2. They feed on living organisms. | 2. They feed on dead and decaying matter. |
| 3. The organism on which it depends is called host. | 3. They depend upon dead and decaying organisms. |
| 4. Example of parasite – Cuscuta | 4. Example of saprotroph – Fungi |
14. Can we imagine life on earth in the absence of photosynthesis?
Answer: No, we cannot imagine life on earth in the absence of photosynthesis. In the absence of photosynthesis there would not be any food. The survival of almost all living organisms directly or indirectly depends upon the food made by the plants. Besides, oxygen which is essential for the survival of all living organisms is produced during photosynthesis. In the absence of photosynthesis, life would be impossible on the earth.
15. Write a note on pitcher plant?
Answer: The pitcher-like structure is the modified part of the leaf. The apex of the leaf forms a lid which can open and close the mouth of the pitcher. Inside the pitcher there are hair which are directed downwards. When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.
16. How nutrients are replenished in the soil?
Answer: Plants absorb mineral nutrients from the soil. So, their amounts in the soil keep on declining. Fertilisers and manures contain plant nutrients such as nitrogen, potassium, phosphorous, etc. These nutrients need to be added from time to time to enrich the soil. The bacterium called Rhizobium present in the roots of legumes plants can take atmospheric nitrogen and convert it into a soluble form. This way Rhizobium bacterium also helps to replenish nitrogen in the soil.
17. Draw a diagram showing photosynthesis.
Answer:
