U2 Key Area 5- Plant Transport Flashcards
How does water and minerals enter through the plant
Root hairs
Why do roots have root hair
Roots have root hairs to increase the surface area. This increases rate of osmosis
What happens when water and minerals enter through the xylem
The water and minerals enter xylem vessels and are transported up the plant to the leaves
What’s the structure of xylem
Xylem forms tube- like structures
What is the happens the xylem becuase it has no nucleus or cytoplasm
As the xylem has no nucleus or cytoplasm the cells are dead
What does lignin do to xylem
Lignin allows the xylem vessels to withstand pressure changes as water moves up the plant
Why do xylem vessels transport water
They transport water for photosynthesis and dissolved mineral salts upwards from the soil, up the stem and to the leaves.
Since water only moves up the plant (one directional)….
The flow in xylem vessels is undirectional
Most photosynthesis occurs in the leaves and they are adapted for this role. What 3 structures are these
- they are flat- large surface area to absorb light
- they are thin to allow light to reach all parts of leaf
- they have lots of chloroplast
Waxy cuticle
Prevents water loss from upper leaf
Lower epidermis
Lower layer, keeps leaf cells together, contains stomata
Stomata
Where carbon dioxide enters/ oxygen and water leaves
Guard cells
Controls opening/ closing of stomata
Phloem
Carries sugar to and from leaf
Xylem
Carries water from roots to leaves
Palisade mesophyll
Tightly packed/ contains lots of chloroplasts, carry out photosynthesis
Spongy palisade
Contains moist air spaces, where gas exchange occurs between air/ cells
Upper epidermis
Upper layer, keeps leaf cells together
What are phloem vessel cells
Phloem vessels have cells joined end-to-end
what is phloem
Phloem is LIVING
What is the structure of phloem (2)
- phloem cells have no nucleus
- their end-walls develops pores, to form sieve plates
How do phloem cells stay alive
Of neighbouring cells called companion cells which contain the cytoplasm and a nucleus
What does phloem transport
Sugar up and down the cell
Is phloem unidirectional
No they are bidirectional
What is transpiration
Transpiration is the process of water moving through a plant and its evaporation through the stomata
What happens in transpiration (3)
- water enters root hairs by osmosis
- the water travels up the plant in xylem vessels
- the water travels to stomata in the leaves where it is lost by evaporation.
The rate of transpiration can be effected by the following factors; (4)
- wind speed
- temperature
- humidity
- surface area
Increased humidity =
Decreased transpiration
Increased temperature =
Increased transpiration
Increased temperature =
Increased transpiration
Increases wind speed
Increased transpiration
Increase surface area =
Increase transpiration
How can the rate if transpiration be measured
By using a potometer
