BRAINCAKEStomata
Gases enter the leaf through pores called stomata.
Each stoma is bordered by guard cells. Guard cells are specialised epidermal cells. They contain chloroplasts and the cellulose of their walls is thicker adjacent to the pore and less thick on the outside farthest from the pore.
When turgor is low, the asymmetric thickening of the cell walls closes the pore.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- osmosis
- The net movement of water molecules from a region of higher water potential to a region of lower water potential through a selectively permeable membrane.
- active transport
- The movement of molecules or ions across a membrane from a region of lower to higher concentration, against the concentration gradient, using ATP and carrier proteins.
- turgor pressure
- The pressure exerted by the contents of a plant cell against the cell wall as water enters by osmosis, making the cell rigid.
More in Exchange of Gases
- Gas Exchange in Fish
- Structure of the Gills
- Counter Current Exchange
- Gas Exchange in Leaves
- Limiting Water Loss in Insects
- Limiting Water Loss in Plants
- The Human Gas Exchange System
- The Lungs
All 28 lessons in Exchange of Gases · All AQA AS-level Biology topics