Lesson 8 of 8

Stomata

Goal: Describe how stomata allow gas exchange in a leaf.

Puzzles for this lesson

Plants exchange gases too. A leaf has tiny pores called stomata that let gases in and out.

Most stomata are on the underside of a leaf. One of them is called a stoma.
In the light, carbon dioxide diffuses in through the stomata. The leaf needs it for photosynthesis.
Oxygen and water vapour diffuse out.
Stomata can open and close. Two guard cells, one each side of the pore, do this.

Your turn

This lesson’s activity starts here in a moment.

I can say where stomata are found.I can state which gases pass through them.

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Gas exchange Taking in one gas and giving out another

Stomata Tiny pores in a leaf that let gases in and out

For teachers: AQA 3.9.4 · Pearson Edexcel 7.5