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๐ฌ Think about it
We breathe to get energy from our food. But do plants breathe too? They have no lungs. Let us use some sprouting seeds and lime water to catch a plant in the act of respiring.
Do plants respire like we do?
- All living beings respire, and plants do too.
- In respiration, glucose is broken down using oxygen.
- This releases carbon dioxide, water, and energy.
- All parts of a plant, green or not, respire.
Example:
Soaked moong seeds in a closed flask give out carbon dioxide as they respire, turning lime water milky.
How Respiration Works
Glucose and oxygen
↓
Glucose breaks down
Oxygen is used to break down the glucose.
↓
Energy is released
This energy is used for growth and life.
↓
Carbon dioxide and water are given out
What is the word equation of respiration?
- Glucose and oxygen are used up.
- Carbon dioxide and water are given out.
- Energy is released for the plant to use.
| Used up | Given out |
|---|---|
| Glucose + Oxygen | Carbon dioxide + Water + Energy |
In this Activity, we will use lime water to show that germinating seeds give out carbon dioxide.
Materials needed
Moong bean seeds, cotton, a conical flask, a two-holed cork, two glass tubes, a rubber pipe, test tubes, and lime water.
Procedure
1. Soak moong seeds in water overnight.
2. Put wet cotton in a conical flask and place the soaked seeds on it.
3. Cover the flask with a two-holed cork and fit two tubes A and B.
4. Leave it undisturbed for 24 hours in the dark.
5. Fill test tubes with lime water and connect the flask to a test tube with a rubber pipe.
6. Compare both test tubes for any colour change.
2. Put wet cotton in a conical flask and place the soaked seeds on it.
3. Cover the flask with a two-holed cork and fit two tubes A and B.
4. Leave it undisturbed for 24 hours in the dark.
5. Fill test tubes with lime water and connect the flask to a test tube with a rubber pipe.
6. Compare both test tubes for any colour change.
Observation
The lime water in the test tube connected to the flask turns milky.
Explanation
Lime water turns milky due to more carbon dioxide. The seeds gave out this carbon dioxide as they respired. So plants respire and release carbon dioxide.
โ Summary
- Soaked seeds in flask
- Connected to lime water
- Lime water turned milky
- Seeds released carbon dioxide
Important Points
- Plants respire to release energy from glucose.
- They take in oxygen and give out carbon dioxide.
- All parts of a plant, green or not, respire.
โ Test Yourself
-
Do plants respire?
View Answer
Yes, all living beings, including plants, respire. -
What is broken down during respiration?
View Answer
Glucose, using oxygen. -
What is released during respiration?
View Answer
Carbon dioxide, water, and energy. -
Why does lime water turn milky?
View Answer
Because of the carbon dioxide released by the respiring seeds. -
Do non-green parts of a plant respire?
View Answer
Yes, all parts, green or non-green, respire.
Important Definitions
- Respiration — the process in which glucose is broken down using oxygen to release carbon dioxide, water, and energy.
- Lime water — a liquid that turns milky in the presence of carbon dioxide.
๐ NCERT Question 1 — Complete the following table
Complete the table comparing the raw materials, products, word equation, and importance of photosynthesis and respiration.
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๐ NCERT Question 10 — Photosynthesis and respiration are
Photosynthesis and respiration are essential to maintain balance in nature. Discuss.
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๐ NCERT Question 8 — Ananya took four test
Ananya set up four test tubes with a snail, a plant, both, and only water, then added a carbon dioxide indicator.
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๐ NCERT Question 5 — X is broken down
X is broken down using Y to release carbon dioxide, Z, and energy. What do X, Y, and Z stand for?
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