Plant Organ System (OCR GCSE Biology A, Combined (Gateway Science Suite)): Flashcards
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14 cards from this deck
Translocation
Translocation
Movement of food substances in phloem up or down the plant
Transpiration
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
Transpiration stream
Transpiration stream
Continuous flow of water up through plant via xylem
Effect of increased temperature on transpiration
Effect of increased temperature on transpiration
Increases rate (faster evaporation & more open stomata)
Effect of increased humidity on transpiration
Effect of increased 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 stomata open for photosynthesis)
Potometer
Potometer
Device measuring water uptake (via bubble movement) to indicate transpiration rate
Guard cells function
Guard cells function
Close and open stomata
Guard cells shape
Guard cells shape
Kidney-shaped
Guard cells wall structure
Guard cells wall structure
Thin outer walls and thick inner walls
Location of most stomata
Location of most stomata
Bottom/lower surface of the leaf
Why stomata mainly on bottom of leaf
Why stomata mainly on bottom of leaf
Allows gas exchange whilst minimising water loss (shaded & cooler)