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Lesson 9 of 16

A plant respires, day and night

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7 min

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A plant makes food in sunlight. What does it do with that food?

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The idea

Respiration breaks down glucose using oxygen. It releases, or gives out, carbon dioxide, water and energy. The plant uses that energy to grow.

Every part of a plant respires, green or not. Seeds respire too. Their carbon dioxide turns lime water, a clear liquid, milky.

Two processes, side by side
PhotosynthesisRespiration
Goes inCarbon dioxide, waterGlucose, oxygen
Comes outGlucose, oxygenCarbon dioxide, water, energy
NeedsSunlight, chlorophyllNothing extra
At night: respiration only. Oxygen goes in.
Step 1 of 3
  1. At night: respiration only. Oxygen goes in.
  2. At noon: food-making runs too. In strong sunlight it makes more oxygen than respiration uses. Extra oxygen goes out.
  3. Respiration goes on both at night and at noon.

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