NCERT Solutions for Class 7 Science Curiosity Chapter 10 Question Answer

NCERT Solutions for Class 7 Science Curiosity Chapter 10  Life Processes in Plants help students understand how plants carry out important life processes like photosynthesis, respiration, and transport of water and food. 

These solutions explain topics in a simple way using easy language, activities, and diagrams. Based on the latest Class 7 Science syllabus, the answers are helpful for learning the concepts better and doing well in exams.

Class 7 Science Curiosity Chapter 10 Life Processes in Plants

Plants are living beings just like animals and humans. To survive and grow, they carry out several important activities called life processes. In this chapter, you will learn how plants make their own food through a process called photosynthesis, how they transport water and nutrients, how they breathe (respire), and how they remove waste from their bodies.

The chapter explains how leaves, roots, stems, and flowers play important roles in these processes. It also includes easy-to-understand experiments and activities that help students see how these life functions work in real life. This chapter builds a strong foundation in science and follows the latest CBSE Class 7 Science syllabus.

Class 7 Science Curiosity Chapter 10 Question Answer

Below are Class 7 Science Chapter 10 Life Processes in Plants Questions and Answers:

Activity 10.1: Let us test some explanations

Take three earthen pots (or used bottles/containers) of the same size filled with garden soil. Plant saplings of similar sizes of a fast-growing plant like chilli or tomato in each pot (Fig. 10.1).  Label the pots A, B, and C.  

Count the number of leaves on each sapling and record your observations.

 Place pot A in direct sunlight. Keep the soil in this pot slightly moist by adding an adequate amount of water every day (Fig. 10.1a).  

Place pot B in direct sunlight, without adding water to the soil (Fig. 10.1b). 

Place pot C in the dark. Keep the soil in this pot slightly moist by adding an adequate amount of water every day (Fig. 10.1c).  

Observe the plants for two weeks and record changes in their height, number of leaves, colour of leaves, and any other changes that may appear.  Record your observations in Table 10.1

What differences did you observe between the plants in the three pots?  Which pot has the plant with the maximum growth?  

Which pot has the plant with the least growth? Analyse the observations recorded in Table 10.1, and discuss them with your teacher and friends.

Answer:

Table 10.1: Effect of Sunlight and Water on Plant Growth

Observations:

After two weeks, the plants in each pot showed the following differences:

• Pot A (sunlight + water):

• The plant showed maximum growth.

• It had more leaves, increased height, and the leaves remained green and healthy.

• This pot provided both sunlight (needed for photosynthesis) and water (required for transport of nutrients and cell function).

• Pot B (sunlight but no water):

• The plant showed limited growth.

• The number of leaves increased slightly, but the plant started to wilt, and the leaves turned yellow.

• Even though it received sunlight, the absence of water led to dehydration and nutrient deficiency.

• Pot C (water but no sunlight):

• The plant showed the least growth.

• It had very few new leaves, and the leaves became pale or yellowish.

• Water was available, but without sunlight, the plant could not perform photosynthesis effectively.

What differences did you observe between the plants in the three pots?
Pot A grew well and looked green and healthy.
Pot B showed signs of dryness and yellowing.
Pot C became pale and weak with poor growth.

Which pot has the plant with the maximum growth?
Pot A – because it had both sunlight and water.

Which pot has the plant with the least growth?
Pot C – due to the absence of sunlight, the plant could not photosynthesize.

Conclusion: This activity proves that both sunlight and water are essential for the healthy growth of plants. Sunlight enables photosynthesis, while water supports nutrient transport and metabolic activities.

Activity 10.2: Let us check (demonstration activity)

The teacher may demonstrate this activity.  Keep a leaf in boiling water for five minutes to soften it.  Dip this leaf in a test tube containing alcohol.  

Place the test tube in a beaker containing boiling water. Wait until the leaf becomes colourless (Fig. 10.2a). (a) Boiling set-up (b) Iodine test Fig. 10.2: Starch test in a leaf Water Alcohol Leaf Spirit lamp Wire gauze Test tube Iodine solution Life Processes in Plants 141  

Take out the leaf and place it on a plate.

Now, put a few drops of diluted iodine solution with the help of a dropper on the decolourised leaf (Fig. 10.2b). Wait for a few minutes and observe. 

If the colour of the leaf changes to blue-black, it indicates the presence of starch.

Caution — Alcohol should never be placed near a heat source directly, as it is highly flammable and can easily lead to fi re and burns

Answer:

This activity helps to test whether starch is present in a leaf, which proves that photosynthesis has taken place.

Steps and Observation:

1. Boil a leaf in water for 5 minutes to soften it.

2. Then, dip the leaf in alcohol placed in a test tube.

3. Place the test tube in a beaker of boiling water (This helps the alcohol remove chlorophyll and make the leaf colourless).

4. Take out the leaf and wash it gently with water to soften it again.

5. Place it on a plate and add a few drops of iodine solution using a dropper.

6. Wait and observe the change in colour.

Result:

• If the leaf turns blue-black, it shows that starch is present.

• Starch is made in the leaves only when photosynthesis occurs, which requires sunlight, carbon dioxide, water, and chlorophyll.

Safety Note:

• Never heat alcohol directly over a flame, as it is highly flammable. Always use hot water as an indirect heat source.

Conclusion:

This activity proves that photosynthesis produces starch in green leaves, and iodine turns blue-black in the presence of starch. Therefore, the blue-black colour confirms that photosynthesis took place in that leaf.

Activity 10.3: Let Us Check (Pages 141-142)

Table 10.2: Presence of starch in green and non-green parts of the leaves of plants

Answer:

In this activity, Bhaskar wanted to find out which parts of the leaf produce starch and how light and chlorophyll affect starch production.

What Bhaskar Did:

1. He took one leaf with both green and non-green patches from:

• A plant kept in sunlight

• A plant kept in the dark for 36 hours

2. Using tracing paper, he marked the green and non-green areas.

3. He then performed the iodine test (like in Activity 10.2) on both leaves to check for starch.

Observations:

Conclusion:

• Green parts of leaves require sunlight to produce starch.

• Non-green parts don't produce starch because they lack chlorophyll.

• Even green parts do not make starch in darkness, proving that sunlight is essential for photosynthesis.

Activity 10.4: Let us Experiment (Demonstration Activity) (Pages 143-144)

Fig. Testing the role of chlorophyll and air, (a) The set-up (b) Iodine test on the leaf

Answer:

This demonstration helps us understand whether carbon dioxide is essential for photosynthesis and the formation of starch in plants.

Experimental Setup:

• A part of a leaf is kept inside a bottle containing caustic soda (which absorbs carbon dioxide).

• The rest of the leaf remains outside the bottle in the open air.

• The leaf gets sunlight, water, and has chlorophyll in both parts.

• After some time, the leaf is tested using iodine solution to check for the presence of starch.

Observations:

Conclusion:

• The part inside the bottle did not turn blue-black, which means no starch was made — because there was no carbon dioxide.

• The part outside the bottle turned blue-black, meaning starch was formed, because it got carbon dioxide.

• This experiment clearly shows that carbon dioxide is necessary for photosynthesis.

Activity 10.5: Let us explore  

Look at Fig. 10.4. Compare the two set-ups labelled as A and B, and analyse.  In Fig. 10.4, set-up A is placed in sunlight, and set-up B is placed in the dark. What difference do you observe in the two set-ups? Do you observe air bubbles emerging in the inverted test tube in set-up A? The gas produced in this set-up caused bubbles to emerge and get accumulated in the inverted test tube. Which gas is this?  

Answer:

Set-up:

• Set-up A: A water plant (like Hydrilla) is placed under sunlight, with an inverted test tube covering the plant.

• Set-up B: A similar arrangement is kept in complete darkness.

Observations:

(i) What difference is observed in the two setups?
In Set-up A (sunlight), bubbles are seen forming in the inverted test tube.
In Set-up B (dark), no bubbles appear.

(ii) Do bubbles emerge in Set-up A?
Yes, bubbles are clearly seen rising and getting collected in the test tube in sunlight.

(iii) What gas is responsible for the bubbles?
The bubbles contain oxygen gas, which is released during photosynthesis.

Conclusion:

• The oxygen gas produced during photosynthesis forms bubbles, which collect in the inverted test tube.

• To confirm its oxygen, a glowing matchstick is brought near the gas. It burns brightly, confirming the gas is indeed oxygen.

• Photosynthesis happens in the presence of sunlight, and oxygen is one of its by-products.

Activity 10.6: Let us examine (demonstration activity) 

The teacher may demonstrate this activity.  Collect a leaf from a plant such as rhoeo, money plant, onion, hibiscus, coleus, or any grass. 

 Put it in a beaker filled with water.

  Carefully peel a thin layer from the lower surface of the leaf.  

Place the peel in a watch glass with water.  

Now, take a microscope slide and carefully put a drop of water on it.  

Using forceps, transfer the peel of the leaf from the watch glass to the slide with the help of forceps.  Put a drop of ink on the leaf peel with the help of a dropper.  

Cover the peel with a coverslip and observe it under a microscope. What do you observe? Do you notice tiny pores on the peel, as shown in Fig. 10.6? These pores are called stomata. Stomata, present on the surface of leaves, help in the exchange of gases.

Answer:

This activity helps students observe stomata, the tiny pores on a leaf’s surface that are responsible for gas exchange in plants.

Steps:

1. Collect a fresh leaf from plants like rhoeo, money plant, hibiscus, coleus, or grass.

2. Place the leaf in a beaker of water.

3. Gently peel off a thin layer from the lower surface of the leaf.

4. Put the peel in a watch glass filled with water.

5. Take a microscope slide and add a drop of water to it.

6. Using forceps, transfer the peel onto the slide.

7. Add a drop of ink on the peel with a dropper (this helps in highlighting the cells).

8. Place a coverslip over the peel carefully.

9. Observe the slide under a microscope.

Observation:

• You will notice tiny pores on the leaf peel.

• These pores are called stomata (singular: stoma).

Conclusion:

• Stomata are small openings present mostly on the lower surface of the leaf

• They help in the exchange of gases (like oxygen and carbon dioxide) and water vapor during photosynthesis and respiration.

Activity 10.7: Let us experiment  

Take two tumblers and label them A and B.  

Fill one-third of each tumbler with water.  

Add a few drops of red ink to tumbler B.  

Obliquely cut the stems of both plants at their base while keeping them inside the water and immediately place one plant in each tumbler, as shown in Fig. 10.7a and Fig. 10.7b.  Observe these plants the next day.

What do you notice? Compare the plant stems placed in the tumblers. Do you observe red colour in the stem, leaves, and flowers of the plant from Tumbler B? Fig. 10.7c and Fig. 10.7d shows the plants after one day. Compare the plant in Fig. 10.7c with that in Fig. 10.7d. A red colour is visible in the stem, leaves, and flowers of the plant in Fig. 10.7d. How did different parts of the plant acquire this red colour? 

Answer:

Objective:

To observe how water and minerals move from the roots to other parts of the plant.

Materials Required:

• Two tumblers (A and B)

• Water

• Red ink

• Two fresh leafy plant stems

• Magnifying glass

Steps:

1. Fill one-third of both tumblers with water.

2. Add a few drops of red ink to Tumbler B.

3. Cut the bottom of both plant stems obliquely while underwater to prevent air bubbles.

4. Place one plant in each tumbler.

5. Leave them overnight.

Observations:

• The plant in Tumbler A (plain water) remains unchanged

• The plant in Tumbler B shows red coloration in the stem, leaves, and flowers the next day.

• When you cut open the stem and observe with a magnifying glass, the red color is seen inside the stem.

Conclusion:

• Red ink travels up the plant through thin tube-like structures called xylem.

• This shows that xylem transports water and minerals from roots to all parts of the plant.

• Just as red ink moved up, similarly, water with dissolved minerals travels through the xylem to reach stems, leaves, and flowers.

• Food, on the other hand, is transported by another tissue called the phloem.

Activity 10.8: Let us find out (demonstration activity

Soak some moong bean seeds in water overnight.  Put a layer of cotton in a conical flake (Fig. 10.9) and moisten the cotton with water to keep it wet.  Place the soaked seeds over the wet cotton in the conical flask.  

Cover the mouth of the conical flask with a cork having two holes.  Fit two tubes A and B through the two holes on the cork, as shown in Fig. 10.9.  Leave it undisturbed for 24 hours in the dark.

Take two test tubes and fill them with lime water.  Cover the mouth of one test tube with a cork having one hole in it.  Dip one glass tube in the test tube through a hole in the cork.  Connect the flask and test tube with a rubber pipe as shown in Fig. 10.9.

Answer

Objective:

To check if seeds respire (i.e., if they release carbon dioxide during respiration).

Materials Required:

• Soaked moong seeds

• Conical flask

• Cotton

• Cork with two holes

• Glass tubes (A and B)

• Two test tubes

• Lime water

• Rubber tubing

Steps:

1. Soak moong seeds in water overnight.

2. Place wet cotton in a conical flask and spread the soaked seeds on top.

3. Close the flask with a cork that has two holes.

4. Insert tube A and tube B through the holes.

5. Keep the flask in the dark for 24 hours.

6. Fill two test tubes with lime water

7. Connect tube B from the flask to one of the test tubes using rubber tubing so that the gas from the flask passes into the lime water

Observations:

• After some time, lime water in the connected test tube turns milky.

• The other test tube (not connected) shows no change.

Conclusion:

• The seeds in the flask are alive and respiring.

• During respiration, they release carbon dioxide (CO₂).

• Lime water turns milky when CO₂ is passed through it, confirming its presence.

• This proves that even germinating seeds respire, just like humans and animals.

InText Questions

Question 1.  How does sunlight contribute to the production of starch in plants?

Answer:
Sunlight helps plants make their food through a process called photosynthesis. The green part of leaves, called chlorophyll, captures sunlight. With the help of sunlight, plants mix carbon dioxide from the air and water from the soil to make a kind of sugar called glucose. This glucose gets stored in the plant as starch.

Question 2.  Which gas from the air is essential in the process of food preparation in plants?

Answer:
Plants need carbon dioxide from the air to make their food. It is one of the main things used in photosynthesis, along with sunlight and water.

Question 1.  Complete the following table.

Answer: 

Question 2.  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 the plants and other organisms that do photosynthesis were gone, there would be no way to make food or release oxygen. Since plants make food that animals eat and give out oxygen that all living beings breathe, their absence would break the food chain and cause all life forms to suffer or die. Life on Earth would not be possible without photosynthesis.

Question 3.  A potato slice shows the presence of starch with iodine solution. Where does the starch in potatoes come from? Where is the food synthesised in the plant, and how does it reach the potato?

Answer:
The starch in potatoes comes from the food made in the leaves through photosynthesis. Leaves use sunlight, water, and carbon dioxide to make glucose, which is then carried to different parts of the plant like the potato. In the potato, this glucose is stored as starch.

Question 4. Does the broad and flat structure of leaves make plants more efficient for photosynthesis? Justify your answer.
Answer:
Yes, the broad and flat shape of leaves helps plants perform photosynthesis more effectively. This structure provides a larger surface area to absorb more sunlight. It also allows for better exchange of gases (carbon dioxide and oxygen) through the stomata, making the photosynthesis process faster and more efficient.

Question 5.  X is broken down using Y to release carbon dioxide, Z, and energy.
X + Y → Carbon dioxide + Z + Energy
What do X, Y, and Z stand for?
Answer:

• X – Glucose

• Y – Oxygen

• Z – Water

This represents the respiration process in living organisms.

Question 6. Krishna set-up an experiment with two potted plants of the same size and placed one of them in sunlight and the other in a dark room, as shown in Fig. 10.10. Answer the following questions — 

(i) What idea might she be testing through this experiment?

 (ii) What are the visible differences in plants in both the conditions?

 (iii) According to you, which leaves of which plants confirm the iodine test for the presence of starch?

Answer:

(i)  She is testing whether sunlight is necessary for the process of photosynthesis in plants.

(ii)  The plant kept in sunlight looks healthy, green, and shows growth due to active photosynthesis. The plant kept in the dark looks dull, pale, and weak because it cannot perform photosynthesis.

(iii) The leaves of the plant kept in sunlight will show the presence of starch when tested with iodine.

Question 7. Vani believes that ‘carbon dioxide is essential for photosynthesis’. She puts an experimental set-up, as shown in Fig. 10.11, to collect evidence to support or reject her idea. 

Answer the following questions — 

(i) In which plant(s) in the above set-up(s) will starch be formed? 

(ii) In which plant(s) in the above set-up(s) will starch not be formed? 

(iii) In which plant(s) in the above set-up(s) will oxygen be generated?

(iv) In which plant(s) in the above set-up(s) will oxygen not be generated?

Answer:

(i) Starch will be formed only in the plant kept in sunlight with access to carbon dioxide.

(ii) Starch will not be formed in plants kept in the dark or in sunlight without carbon dioxide.

(iii) Oxygen will be produced only in the plant kept in sunlight with carbon dioxide.

(iv) Oxygen will not be produced in any of the plants except the one that has both sunlight and carbon dioxide.

Question 8. 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 a snail; in test tube B, she kept a water plant; in test tube C, she kept both a snail and a plant. In test tube D, 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:

Ananya wants to study how living organisms like snails and plants affect the level of carbon dioxide in water. Specifically, she is testing the processes of respiration (by animals) and photosynthesis (by plants). She used a carbon dioxide indicator which changes color based on the amount of CO₂ present in each test tube.

Expected Observations:

Question 9. Design an experiment to observe if water transportation in plants is quicker in warm or cold conditions.

Answer:
To observe if temperature affects water transportation in plants:

1. Take two similar healthy potted plants.

2. Add red or blue food coloring to two containers of water.

3. Place one plant in a warm environment (like near a window in sunlight).

4. Place the other plant in a cool environment (like a shaded room).

5. Water both plants using the colored water at the same time.

6. After a few hours, observe the stems and leaves.

Observation:
The plant in the warm condition will absorb colored water faster. This shows that water transportation is quicker in warm conditions due to increased evaporation and transpiration.

Question 10. Photosynthesis and respiration are essential to maintain balance in nature. Discuss.

Answer:
Photosynthesis and respiration are two opposite but connected processes that help maintain the natural balance of gases in the atmosphere.

• In photosynthesis, plants take in carbon dioxide and release oxygen.

• In respiration, both plants and animals use oxygen and release carbon dioxide.

This continuous exchange keeps the levels of oxygen and carbon dioxide balanced in nature. If either process stops, it can disrupt life on Earth. That’s why both are essential for the survival of living organisms.

NCERT Solutions for Class 7 Science Curiosity Chapter 10 PDF Download

Students can download the NCERT Solutions for Class 7 Science Curiosity Chapter 10 Life Processes in Plants from the link given below.

These solutions are designed to help students understand key concepts such as photosynthesis, respiration, and the transportation of water and nutrients in plants.

By using these solutions, students can clarify doubts, revise effectively, and prepare well for their exams. The PDF format makes it easy to access and study anytime, even offline.