Leaf structure
The structure of a leaf has adaptations so that it can carry out A chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic. effectively.
A leaf needs:
- a way to transport water to the leaf, and A simple sugar used by cells for respiration. to other parts of the plant
- a way to exchange carbon dioxide and oxygen
- the ability to absorb light energy efficiently
Absorbing light energy
Light absorption happens in the Plant tissue containing closely packed cells in the upper layer of a leaf. tissue of the leaf. Palisade cells are column-shaped and packed with many Contains the green pigment chlorophyll; the site of photosynthesis.. They are arranged closely together so that a lot of light energy can be absorbed.
Features of leaves and their functions
| Feature | Function |
| Large surface area | Maximise light absorption |
| Thin | Short distance for carbon dioxide to diffuse into leaf cells |
| Cuticle | A waxy waterproof layer which reduces water loss, it is transparent to allow light through the leaf |
| Feature | Large surface area |
|---|---|
| Function | Maximise light absorption |
| Feature | Thin |
|---|---|
| Function | Short distance for carbon dioxide to diffuse into leaf cells |
| Feature | Cuticle |
|---|---|
| Function | A waxy waterproof layer which reduces water loss, it is transparent to allow light through the leaf |
The role of stomata
The Tiny holes in the epidermis (skin) of a leaf. They control gas exchange by opening and closing and are involved in loss of water from leaves. Singular is stoma. control gas exchange in the leaf. Each stoma can be open or closed, depending on how Enlarged and swollen with water. Having turgor. Description of a plant cell in which the vacuole has swollen due to water gain by osmosis. its guard cells are.
The stomata can open and close to:
- regulate transpiration
- allow gas exchange
The movement of molecules from an area of higher concentration to an area of lower concentration. of carbon dioxide, oxygen and water vapour into (or out of) the leaf is greatest when the stomata are open, during the day.