3.1 (P2) Exchange Systems In Plants Flashcards
How does carbon dioxide enter leaves?
Via diffusion through the stomata
Where are water and mineral ions absorbed?
By the roots
How is the surface area of roots increased?
Root hair cells
How is water taken into and transported around a plant?
Via osmosis through the roots
Transported up by Xylem
What are Xylem?
Dead cells forming a hole like tube
How are mineral ions taken into and transported around a plant?
Via active transport through the roots
Transported around by Phloem
What is the purpose of Phloem?
They transport and direct minerals and nutrients where they need to be as they have small perforated holes allowing movement
How does a high concentration of mineral ions inside the plants affect water movement?
When active transport takes place in the roots there is now a higher concentration of ions inside
If there is a higher concentration of minerals ions inside there is a lower concentration of water inside
This helps bring more water in via osmosis as there is a steeper concentration gradient
What is transpiration?
The process by which moisture is carried through plants and then evaporated from the leaves
How much water is lost by evaporation?
90% lost
10% used in photosynthesis
What is a constant water flow useful for?
Turgidity
Photosynthesis
Steep concentration gradient
What are stomata?
Holes in the leaf that allow gases to be transferred
What are the stomata protected and controlled by?
Guard cells
What leaves via the stomata?
Oxygen and water vapour
Where is there more stomata? Why?
Underneath the leaf (lower epidermis)
So they lose less water (needed for turgidity)
What are guard cells like when sunny? Dark?
Sunny - swollen causing the stomata to be open
Dark - shrunken causing the stomata to be closed
How are leaves adapted for efficient gas exchange?
Large surface area: flat shape and air spaces within
High concentration gradient: constant flow of water internally, constant flow of air externally
Short diffusion distance: the leaf is a few cells thick
What factors affect transpiration?
Dry and windy
Steeper concentration gradient (moist inside and dry outside)
Hot
Evaporation happens faster
