Plants

Structure – Leaves stem roots

Leaves

Function of leaves

 Trap light energy for photosynthesis Producing sugar from photosynthesis  Exchange of gases – oxygen and carbon dioxide

Structure

Wide

Helps to catch more light energy

Thin

Help get carbon dioxide from bottom to top of leaf for photosynthesis

Leaf structure

Greener on top CO 2 here gets in

Leaf diagram – palisade layer Most chlorophyll CO 2

Leaf cell palisade

Position?

Upper surface of leaf

Features?

Box shape Chloroplasts

Function?

Photosynthesis

Gas exchange

 Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf  They have small holes called stomata on the under surface  Each hole is open & closed by 2 guard cells

Leaf diagram – stoma and guard cells

Stoma position

Stoma is a small hole

Its size is controlled by 2 guard cells closed open

Stoma function is for gas exchange in the leaf Guard cell

oxygen Provided plant is photosynthesising Carbon dioxide

Stomata open and close at different times of the day When it is light the plant needs CO 2 for photosynthesis so the stoma open At night (darkness) they close

Gas exchange

Roots – function and structure

 Hold plant in position  Absorb water and minerals from the soil  Specialised cells to increase surface area for water intake

Wheat seed

Root hairs Fragile parts of cells that grow from the main root They massively increase the surface area for absorption

Root hair cells

(x150)

Root ‘B’ has had the hairs damaged -

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