Saved for later
Food that is not used now is kept as a reserve.
Energy in the dark
A plant can make food only while the sun shines. But its cells need energy at night too.
How does the plant get energy at night?
What this lesson covers
The idea
Carbohydrates not used immediately are stored in plants as starch, an internal energy reserve; similarly, some energy derived from our food is stored in our body as glycogen.
Energy in the dark
A plant can make food only while the sun shines. But its cells need energy at night too.
How does the plant get energy at night?
- It does not need any energy at night
- It uses food that it saved earlier
- It takes in food from the soil at night
Store it, then use it
Start with the plant. Press Sunny hour a few times, then Dark hour. Then switch to You and do the same with meals.
Not used now, kept for later
Carbohydrates not used immediately are stored in plants as starch, an internal energy reserve to be used as and when required. Similarly, some of the energy from the food we eat is stored in our body as glycogen.
Both are reserves: energy kept safe for the time it is needed.
- A plant | Our body
- Makes carbohydrate in photosynthesis | Gets energy from the food we eat
- Stores what is not used immediately as starch | Stores some of the energy as glycogen
- Starch is its internal energy reserve | Glycogen is the energy store in the body
Notes
Carbohydrates not used immediately are stored in plants as starch, an internal energy reserve; similarly, some energy derived from our food is stored in our body as glycogen.
Check yourself
Ravi eats nothing from dinner till breakfast. Where does his body get energy overnight?
In the sunny hours of a day, a leaf makes 10 packs of carbohydrate. The plant uses 6 packs immediately. How many packs are stored as starch?
Answer: 4 packs
10 made, 6 used now. 10 − 6 = 4 packs are not used immediately, so they are stored as starch.
Which pair is correct?
What does a plant do with carbohydrate that it does not use immediately?
- From the glycogen stored in his body — correct. Yes! Some of the energy from his food was stored as glycogen.
- From starch stored in his body. Starch is the reserve of plants. Our body stores glycogen.
- From nowhere: a sleeping body needs no energy. Even when we are not doing anything, energy is needed to keep the body in order.
- Plants store glycogen, and our body stores starch. It is the other way round. Plants keep starch and we keep glycogen.
- Plants store starch, and our body stores glycogen — correct. Yes! Both are energy reserves.
- Plants store starch, but our body stores nothing. Some of the energy from the food we eat is stored in our body as glycogen.
- Throws it out of the leaf. It keeps it. Starch is stored for the time when the plant needs it.
- Turns it back into carbon dioxide and water at once. It does not undo its work. It stores the carbohydrate as starch.
- Stores it as starch, to be used as and when required — correct. Yes! Starch is its internal energy reserve.