In this article, we will provide you with solutions to the NCERT questions of Life Processes in Plants. This chapter in Class 7 Curiosity covers important topics such as photosynthesis, respiration, transport of water and food in plants, and the importance of plants in nature. These solutions are written in very simple and easy language so that students can understand the concepts quickly and prepare well for their exams and homework.
Q1. Complete the following table
Answer:
I. Photosynthesis
- Raw materials: Carbon dioxide, water, sunlight, chlorophyll
- Products: Food (glucose), oxygen
- Word equation: Carbon dioxide + Water + Sunlight → Glucose + Oxygen
- Importance: It makes food for plants and gives oxygen to living things.
II. Respiration
- Raw materials: Food (glucose), oxygen
- Products: Carbon dioxide, water, energy
- Word equation: Glucose + Oxygen → Carbon dioxide + Water + Energy
- Importance: It gives energy to living things for all activities.
Q2. Imagine a situation where all the organisms that carry out photosynthesis on the earth have disappeared. What would be the impact of this on living organisms?
Answer:
If all photosynthetic organisms disappear, no food and oxygen will be produced. Animals and humans will not survive because they need food and oxygen. Life on Earth will slowly end.
Q3. A potato slice shows the presence of starch with iodine solution. Where does the starch in potato come from? Where is the food synthesised in the plant, and how does it reach the potato?
Answer:
The starch in potato comes from the food made by green leaves. Food is prepared in the leaves by photosynthesis. This food is carried through tubes in the plant to the potato, where it is stored as starch.
Q4. Does the broad and flat structure of leaves make plants more efficient for photosynthesis? Justify your answer.
Answer:
Yes, broad and flat leaves help plants in photosynthesis. They can catch more sunlight and take in more carbon dioxide from air. This helps the plant make more food.
Q5. X is broken down using Y to release carbon dioxide, Z, and energy.
X + Y → Carbon dioxide + Z + Energy
X, Y, and Z are three different components of the process. What do X, Y, and Z stand for?
Answer:
The given word equation represents the process of phytosynthesis that happens in plants.
- X = Glucose
- Y = Oxygen
- Z = Water
Q6. Krishna set-up an experiment with two potted plants of same size and placed one of them in sunlight and the other in dark room, as shown in Fig. 10.10. Explain the experiment for photosynthesis and answer the following questions.
(i) What idea might he be testing through this experiment?
Answer:
He is testing whether sunlight is needed for photosynthesis.
(ii) What are the visible differences in plants in both the conditions?
Answer:
The plant in sunlight looks green and healthy. The plant kept in dark becomes weak and pale.
(iii) According to you, leaves of which plants confirm the iodine test?
Answer:
Leaves of the plant kept in sunlight will confirm the iodine test because starch is formed there.
Q7. Vani believes that ‘carbon dioxide is essential for photosynthesis’. She puts an experiment set-up, as shown in Fig.10.11, to collect evidence to support or reject her idea.
(i) In which plant(s) in the above set-up(s) will starch be formed?
Answer:
Starch will be formed in plants (a) and (b).
(ii) In which plant(s) in the above set-up(s) will starch not be formed?
Answer:
Starch will not be formed in plants (c) and (d).
(iii) In which set-up(s) will oxygen be generated?
Answer:
Oxygen will be generated in set-ups (a) and (b).
(iv) In which plant(s) in the above set-up(s) will oxygen not be generated?
Answer:
Oxygen will not be generated in set-ups (c) and (d).
Q8. Ananya took four test tubes and filled three-fourth of each test tube with water. She labelled them A, B, C and D (Fig. 10.12). In test tube A she kept snail in it. She kept a water plant in test tube B and a plant. In test tube C, she kept only water. Ananya added a carbon dioxide indicator to all the test tubes. She recorded the initial colour of water and observed if there are any colour changes in the test tubes after 2–3 hours. What do you think she wants to find out? How will she know if she is correct?
Answer:
She wants to find out how plants and animals use and release carbon dioxide.
- The snail in tube A will release carbon dioxide, so the indicator colour will change.
- The plant in tube B will use carbon dioxide in sunlight, so the colour change will be less.
- Tube C will show no change because it has only water.
Q9. Design an experiment to observe if water transportation in plants is quicker in warm or cold conditions.
Answer:
Take two similar plants. Keep one plant in a warm place and the other in a cold place. Put both stems in coloured water. After some time, check which plant shows colour in leaves faster. The plant in warm condition will show faster water movement.
Q10. Photosynthesis and respiration are essential to maintain balance in nature. Discuss.
Answer:
Photosynthesis gives food and oxygen to living things. Respiration uses food and oxygen to release energy and gives back carbon dioxide. Both processes help maintain balance of oxygen and carbon dioxide in nature.