Nutrition in plants Solutions Class 7 Science BOSEM

Explore comprehensive solutions for ‘Nutrition in Plants’ from Class 7 Science (BOSEM). Learn about autotrophic and heterotrophic nutrition, photosynthesis, and more in easy-to-understand explanations

Nutrition in Plants Solutions

Find detailed solutions for ‘Nutrition in Plants’ with all questions and answers from Class 7 Science. Understand concepts like photosynthesis, types of nutrition, and more with clear explanations

Q1. Why do organisms take food?

Ans: Organisms take food because:

1. Food helps in the growth and development of the body
2. Food provides energy for various physical activities.
3. Food is also needed for replacement and repair of damaged tissues.
4. Food helps in the proper functioning of the body.
5. Food protects our bodies from diseases and ailments.

Q2. Distinguish between parasites and a saprotroph.

Ans:

Q3. How would you test the presence of starch in leaves?

Ans: The presence of starch in leaves can be tested by performing an iodine test of the leaves. In this process, the chlorophyll in green leaves is removed by boiling the leaves in alcohol and then putting two drops of iodine solution in them. If the colour of the solution changes to blue, it indicates the presence of starch.

Q4. Give a brief description of the process of synthesis of food in green plants.

Ans: The process of synthesizing food in green plants is called photosynthesis.
photosynthesis can be described briefly in the following ways.
The synthesis of food in green plants takes place in the presence of sunlight, carbon dioxide and water in which the green pigment called chlorophyll present in green leaves captures the solar energy. During this process, the synthesis of food occurs in the form of carbohydrates or glucose with the release of oxygen gas.

Carbon dioxide + Water ——————–>Carbohydrate + Oxygen

Q5. Show with the help of a sketch that plants are the ultimate source of food

Ans:

Q6. Fill in the blanks

1. Green plants are called autotrophs since they synthesise their own food.
2. The food synthesized by plants is stored as starch.
3. In photosynthesis, solar energy is absorbed by the pigment called chlorophyll.
4. During photosynthesis plants take in carbon dioxide and release Oxygen gas.

Q7. Name the following

1. A parasite plant with yellow, slender and branched stem.
   👉 Cuscuta.
2. A partially autotrophic plant.
   👉 Pitcher plant
3. The pores through which leaves exchange gases.
   👉 Stomata

Q8. Tick the correct answer

1. Cuscuta is an example of
   Ans: Parasite
2. The plants which traps and feeds on insects is
   Ans: Pitcher plant

Q9. Match the following

Q10. Mark ‘T’ if the statement is true and ‘F’ if it is false.

(i) Carbon dioxide is released during photosynthesis.
Ans: F
(ii) Plants which synthesize their food are called saprotrophs
Ans: F
(iii) The product of photosynthesis is not a protein.
Ans: T
(iv) Solar energy is converted into chemical energy during photosynthesis
Ans: T

Q11. Choose the correct option from the following:

a) Which part of the plants take in carbon dioxide from the air for photosynthesis?
(i) Root hair (ii) Stomata (iii) Leaf veins (iv) Petals
Ans: Stomata

b) Plants take carbon dioxide from the atmosphere mainly through their
(i) roots (ii) stem (iii) flowers (iv) leaves
Ans: leaves

Q12. Why do farmers grow many fruits and vegetables crops inside large green houses? What are the advantages to the farmers?

Ans: Farmers grow many fruits and vegetable crops inside large green houses because

(i) Green houses provides required temperature for the crops,
(ii) Green houses prevents the crops from wind, cold, insects, pests etc.

The advantages of farming in green houses are
(i) better yield or increase in productivity of fruits and vegetable crops,
(ii) it requires less efforts of farmer and make them easier to grow and produce more

Nutrition in Plants Extra Questions

Discover extra questions on ‘Nutrition in Plants’ for Class 7 Science. Practice with a variety of important questions and answers to deepen your understanding of key concepts like photosynthesis and types of nutrition

Q1. What are nutrients?

Ans: The components of food like carbohydrates, fats, proteins, vitamins and minerals which are necessary for the growth and development of an organism are called nutrients.

Q2. What is nutrition?

Ans: Nutrition is the mode of taking food by an organism and its utilization by the body.

Q3. How are plants classified?

Ans: Plants are classified based on their mode of nutrition.

Q4. What are autotrophs or autotrophic plants?

Ans: Autotrophic plants are those plants which can manufacture their own food from simple inorganic substances.
Example: All green plants.

Q5. What are heterotrophs or heterotrophic plants?

Ans: Heterotrophic plants are those plants which cannot manufacture their own food but depend upon other organisms for their food. Examples: Fungi, parasites etc.

Q6. What are various modes of plant nutrition?

Ans: The various modes of plant nutrition are

1. Autotrophic mode of nutrition and
2. Heterotrophic mode of nutrition.

Q7. What is the Autotrophic mode of nutrition?
Ans: The mode of nutrition in which organisms make food themselves from simple inorganic substances is called the autotrophic mode of nutrition.

Q8. What is a Heterotrophic mode of nutrition?

Ans: The mode of nutrition in which organisms depend on plants and other organisms for their food is called a heterotrophic mode of nutrition.

Q9. In which part of the plant food is prepared?

Ans: Food is prepared mainly in the leaves and some green parts (green stem and green branches) of plants as in the case of desert plants where there are no leaves.

Q10. What are the food factories of plants?

Ans: Leaves are the food factories of plants.

Q11. What are stomata?

Ans: The tiny pores present on the lower surface of leaves surrounded by guard cells are called stomata.

Q12. What are vessels?

Ans: Vessels are like pipes which run through the root, the stem, the branches and the leaves for transportation of water and minerals. They form a continuous path or passage for the nutrients to reach the leaf.

Q13. Name the pigment which makes the leaves green.

Ans: Chlorophyll.

Q14. What is the ultimate source of energy?

Ans: The Sun is the ultimate source of energy.

Q15. What will happen if there are no green plants on the earth?

Ans: There would not be any living organisms on Earth in the absence of green plants.

Q16. What are algae?

Ans: The slimy green patches in ponds or stagnant water bodies which are green in colour due to the presence of chlorophyll and can prepare their own food by photosynthesis are called algae.

Q17. Name the chemical which is used to test the presence of starch in the leaf.

Ans: Iodine.

Q18. What is photosynthesis?

Ans: The process by which plants make their own food in the presence of sunlight, carbon dioxide, water, and chlorophyll is called photosynthesis.

Q19. What are the raw materials for photosynthesis?

Ans: Chlorophyll, carbon dioxide, water and sunlight are the raw materials for photosynthesis.

Q20. What is the end product of photosynthesis?

Ans: The end product of photosynthesis is Carbohydrate and oxygen.

Q21. Name the process through which the autotrophs or green plants prepare their food.

Ans: Photosynthesis.

Q22. What are the conditions necessary for photosynthesis?

Ans: The conditions necessary for photosynthesis are

Q23. What is the role or importance of chlorophyll in photosynthesis?

Ans: Chlorophyll is necessary because it can trap the energy from the sunlight and helps to carry out the process of photosynthesis. Without chlorophyll, plants cannot manufacture their food.

Q24. How does carbon dioxide enter into the leaf?

Ans: Carbon dioxide from the air is taken in through tiny holes/pores called stomata. These pores are surrounded by guard cells. During daytime when the guard cells are turgid, the stomata remain open and carbon dioxide enters into the leaf.

Q25. Explain the process of photosynthesis in plants.

Ans: Photosynthesis is the process of manufacturing their own food by green plants using chlorophyll in the presence of carbon dioxide, water and sunlight to produce carbohydrates and oxygen.

The process of photosynthesis takes place in the leaves of a plant where the green pigment called chlorophyll is present along with other requirements. i.e., carbon dioxide and water. The chlorophyll traps light energy from sunlight while water is transported to the leaves by the vessels. Then, carbon dioxide enters the leaves through the stomata. Thus, photosynthesis occurs in this way. Carbohydrates are synthesised during the process along with the release of oxygen gas.

The process of photosynthesis can be represented by the following reaction

Insert image.

Q26. Write the importance of photosynthesis.

Ans: The importance of photosynthesis is:

Q27. How are heterotrophic plants categorized? Explain with examples:

Ans: Heterotrophic plants are categorized in the following ways:

1. Saprophytic Plants: Those plants which grow and live on death and decaying organic matter of plants and animals are called saprophytic plants. Example: Monotropa, coral root.
2. Parasitic plants: those plants which obtain their nutrition from other living plants or hosts are called parasitic plants: Examples are Cuscuta and Rafflesia.
3. Insectivorous plants: The insect-eating plants which absorb the nutrients mainly nitrogen from the insects by secreting a juice are called insectivorous plants. Eg: pitcher plant, Venus flytrap.
4. Symbiotic plants: Plants which live together with other organisms sharing shelter and nutrients, in which both the organisms are mutually benefit are called symbiotic plants. Example: Rhizobium with leguminous plants. Lichens.

Q28. Differentiate between autotrophic and heterotrophic modes of nutrition.

Ans: Autotrophic mode of nutrition

1. This type of nutrition is found in green plants only.
2. These green plants can manufacture their own food.
3. Carbon dioxide and water are utilized to prepare food in the presence of sunlight and chlorophyll.

Heterotrophic mode of nutrition.

1. It is found in all organisms other than green plants.
2. These organisms cannot prepare their own food but depend on others.
3. No such process takes place in such a mode of nutrition.

Q29. What is the mode of nutrition of Cuscuta?

Ans: Parasitic mode of nutrition.

Q30. What are insectivorous plants?

Ans: The insect-eating plants which absorb the nutrients mainly nitrogen from the insects by secreting a juice are called insectivorous plants.

Q31. What do you mean by symbiotic relationship?

Ans: The relationship between some organisms in which they live together and share both shelter and nutrients is called a symbiotic relationship.

Q32. What are Lichens?

Ans: Lichens are symbiotic plants in which two organisms live together with mutual benefits to each other- an algae, which contains chlorophyll and a fungus. The fungus provides shelter, water and minerals to the algae and, in return, the alga prepares and provides food to the fungus.

Q33. In which form do plants use nitrogen?

Ans: Plants use nitrogen in soluble form.

Q34. Name the bacteria which convert atmospheric nitrogen into soluble form.

Ans: Rhizobium bacteria present in the roots of leguminous plants like grams, peas, beans etc.

Q35. What is the importance of rhizobium bacteria?

Ans: Plants cannot use nitrogen from the atmosphere directly they need nitrogen in a soluble form. Rhizobium bacteria can fix atmospheric nitrogen and convert it into a usable form which the plants itself cannot do. Rhizobium lives in the roots of leguminous plants like grams, peas, beans, etc., and provides them with nitrogen. In return, the plants provide food and shelter to the bacteria. Thus, they have a symbiotic relationship which is of great significance for the farmers by reducing the use of nitrogenous fertilizers.

Q36. How are nutrients replenished in the soil?

Ans: The amounts of minerals and nutrients keep on decreasing as plants absorb it from the soil. In order to replenish these deficiencies of nutrients, fertilizers and manures containing nutrients such as nitrogen, potassium, phosphorus etc., need to be added from time to time to enrich the soil. The plants will remain healthy if we can fulfil their nutrient requirements.

Q37. Name the units which make the bodies of a living organism.

Ans: The units that make the bodies of a living organism are called cells.

Q38. What are the three main parts of a cell?

Ans: The three main parts of a cell are

1. Cell membrane
2. Nucleus
3. Cytoplasm

Q39. Perform an activity to show that photosynthesis requires sunlight.

Ans: Take a potted plant and keep it in a dark place for 2-3 days so that the leaves get de-starched. Cover a part of one of its leaves with one of its leaves with a strip of black paper. Make sure that you cover both sides of the leaf. Now place this plant in sunlight for 3-4 hours. Pluck the selected covered leaf and remove the black paper covering it. Place this leaf in a beaker containing water and boil it for about 10 minutes. This removes the chlorophyll. Take out the leaf and wash it under running water. Place this leaf in the Petri dish and put a few drops of iodine solution on it. Now observe the colour change.

The leaf turns blue-black except in the covered region. As this covered region did not receive light, photosynthesis did not occur. Hence no starch was formed there. The uncovered region received light and starch was formed there due to photosynthesis.

Thus, the above activity shows that sunlight is necessary for photosynthesis.

Q40. Perform an activity to show that fungi grow easily on dead and decaying organic matter.

Ans: Take a piece of bread moisten it with water and leave it in a moist and warm place for 2-3 days or until fluffy patches appear on them. After a few days, some bluish-green patches are seen to appear on the bread. If it is observed under a microscope or a magnifying glass, cotton-like threads are seen spreading on the piece of bread. These are called fungi and they absorb the nutrients from the dad and decaying bread. The same activity can be conducted on different fruits, vegetables, leathers etc.