Q1.
Do plants also respire like we do?
Answer
Yes. All living beings respire, and plants are no exception. Like us, plants take in oxygen, use it to break down glucose, and release carbon dioxide, water and energy.
The difference is only in the arrangement, not in the process: we have lungs and a breathing system, while a plant has no lungs. Gases simply diffuse in and out through the stomata of leaves and through the surface of young stems and roots. All parts of a plant, green or non-green, carry out respiration — by day and by night.
Why we do not notice it: in daylight a green leaf is also photosynthesising, and photosynthesis uses up carbon dioxide much faster than respiration produces it. That is why Activity 10.8 uses germinating seeds kept in the dark — no photosynthesis is possible, so respiration alone can be detected.