adaptation for gas exchange in plants unit 2
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Image occlusion: name the hidden labels
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What is the cuticle?
Waxy transparent layer
Allows light thru to palisade mesophyll
Reduces water loss by evaporation on top of leaf
Allows light thru to palisade mesophyll
Reduces water loss by evaporation on top of leaf
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What is the palisade mesophyll?
Main photosynthetic layer packed with chloroplasts
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What is the spongy mesophyll?
Surrounded by air spaces for easy diffusion
Mesophyll cell membranes=site of gas exchange
Mesophyll cell membranes=site of gas exchange
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What is the stomata?
Stomatal pores- allow gas exchange down conc gradient
Gases diffuse thru intracellular spaces to and from photosynthetic cells
Gases then diffuse in the moist lining and into the cells
Pores opened and closed during day / night
Gases diffuse thru intracellular spaces to and from photosynthetic cells
Gases then diffuse in the moist lining and into the cells
Pores opened and closed during day / night
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What controls the stomatal pores?
Guard cells
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Why do stomatal pores open in day?
Allows CO2 to enter the air spaces and cells to be used for photosynthesis
Sunlight= photosynthesis
Sunlight= photosynthesis
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Why do stomatal pores close at night?
Reduces water loss
No sunlight= no photosynthesis
No sunlight= no photosynthesis
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What is the upper epidermis?
Transparent layer
Light can easily penetrate photosynthetic layers
Light can easily penetrate photosynthetic layers
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What is the vascular bundle?
Xylem- carry water from roots
Phloem- carry sucrose to other parts of
plant
Bundle sheath parenchyma
Phloem- carry sucrose to other parts of
plant
Bundle sheath parenchyma
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How are leaves adapted to photosynthesis?
Large SA
Thin with transparent cuticle and upper epidermis
Palisade cells packed with chloroplasts
Thin with transparent cuticle and upper epidermis
Palisade cells packed with chloroplasts
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Image occlusion: name the hidden labels
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Image occlusion: name the hidden labels
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How do the guard cells open the stomatal
pores? (opposite for close)
pores? (opposite for close)
In light- chloroplasts in guard cells photosynthesise, produce ATP
ATP used for active transport of K+ ions to guard cells
Starch converted to malate
Malate and K+ ions lower WP of g cells, water drawn in by osmosis
G cell inner wall thickens unevenly causing to bend as swell..
..Stomatal pore opens
ATP used for active transport of K+ ions to guard cells
Starch converted to malate
Malate and K+ ions lower WP of g cells, water drawn in by osmosis
G cell inner wall thickens unevenly causing to bend as swell..
..Stomatal pore opens