Leaf Structure and Gaseous Exchange WALT – Explain how CO2 and Oxygen enter/ leave the plant WILF – Function of leaf Diagram of leaf Diagram of stomata inc 2 guard cells Questions answered

Leaves

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

Structure Helps to catch more light energy 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 CO2 gets in here

Leaf diagram – palisade layer Most chlorophyll CO2

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 oxygen Guard cell Provided plant is photosynthesising Carbon dioxide

Stomata open and close at different times of the day When it is light the plant needs CO2 for photosynthesis so the stoma open At night (darkness) they close

Gas exchange

What controls the flow of gases into and out of the leaf? Complete the sentence : Theses stomata are made from 2 ___________ cells. They open during the day to let __________ into the leaf and _____ at night .

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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