Plant Organ System (OCR GCSE Biology A (Gateway Science Suite)): Flashcards
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15 cards from this deck
Define translocation
Define translocation
Movement of food substances in phloem up or down the plant
Purpose of translocation
Purpose of translocation
For immediate use or storage
Define transpiration
Define transpiration
Loss of water vapour from leaves and stems of plant
Why does transpiration occur?
Why does transpiration occur?
Consequence of gaseous exchange via open stomata
What is the transpiration stream?
What is the transpiration stream?
Continuous flow of water through the plant
Effect of increased temperature on transpiration
Effect of increased temperature on transpiration
Increases rate - faster evaporation & more stomata open
Effect of high humidity on transpiration
Effect of high humidity on transpiration
Decreases rate - reduced concentration gradient
Effect of increased wind on transpiration
Effect of increased wind on transpiration
Increases rate - steeper concentration gradient
Effect of increased light on transpiration
Effect of increased light on transpiration
Increases rate - more photosynthesis so more stomata open
What is a potometer?
What is a potometer?
Device measuring water uptake by tracking bubble movement
Function of guard cells
Function of guard cells
Close and open stomata
Shape of guard cells
Shape of guard cells
Kidney-shaped
Guard cell wall structure
Guard cell wall structure
Thin outer walls and thick inner walls
Where are most stomata found on a leaf?
Where are most stomata found on a leaf?
On the bottom of the leaf
Why are stomata on the bottom of the leaf?
Why are stomata on the bottom of the leaf?
Minimises water loss - shaded and cooler surface