Gas Exchange In The Leaf Of A Plant

Front 1

How do plants exchange gases?

Back 1

Depends on the balance between the rates of photosynthesis and respiration.
When photosynthesis is taking place, although some carbon dioxide comes from respiration of cells, most of it has to be obtained from the air. And in the same way, some oxygen from photosynthesis is used in respiration but most of it diffuses out of the plant.
When photosynthesis is not occurring (in the dark) oxygen diffuses into the leaf to be used for respiration. Carbon dioxide produced during respiration diffuses out

Front 2

What is the structure of a dicotyledonous plant leaf?

Back 2

-Upper epidermis
-Palisade cells
- Mesophyll cells and air spaces within them
-Lower epidermis
- Stomata with surrounding guard cells

Front 3

How is the leaf adapted for efficient gas exchange?

Back 3

- a thin, flat shape that provides a large surface area
- many small pores, called stomata in the lower epidermis
-numerous interconnecting air spaces occurring throughout the mesophyll

Front 4

The stomata

Back 4

Stomata are minute pores that occur mainly on the leaves. Each stoma is surrounded by a pair of special cells called guard cells.
Guard cells can open and close the stomatal pore to control the rate of gas exchange.
This is very important because terrestrial organisms lose water by evaporation.