CB6 Plant Transport Flashcards
What is the function of root hair cells?
Absorb water and mineral ions from the soil.
What 3 specialisations do root hair cells have?
Many mitochondria, large permanent vacuole, hair-like extension
What is the function of xylem vessels?
Transport water and mineral ions up the plant.
What 3 specialisations do xylem vessels have?
Lignified cell walls (strengthened with lignin) ,dead cells, no end cell walls,
What is the function of phloem vessels?
Transport sugar in the plant to where it is required.
What 2 cells make up phloem vessels?
Sieve tube cells, companion cells
What 3 specialisations do sieve tube cells have?
Little cytoplasm / few organellese, sieve plates, pores to allow substances through the ends
What 3 specialisations do companion cells have?
Many mitochondria, large nucleus, pores
What is transpiration?
The evaporation and diffusion of water from inside the plant to outside.
What does transpiration occur through?
Stomata
What cells surround the stomata?
Guard cells
What 3 gases are exchanged through the stomata?
oxygen, carbon dioxide, water vapour
What happens to the guard cells in order to open the stomata?
Water diffuses in by osmosis causing the guard cells to become turgid.
What happens to the guard cells in order to close the stomata?
Water diffuses out by osmosis causing the guard cells to become flaccid.
What is the transpiration stream?
The flow of water from the soil into the roots, up the xylem, out of the leaves into the atmosphere.
What 4 environmental conditions affect the rate of transpiration?
light intensity, temperature, air movement, humidity
What is the effect of increasing humidity on the rate of transpiration?
Decreases
What 2 environmental conditions affect the water vapour concentration gradient between the leaf and atmosphere?
humidity, air movement
What environmental condition affects whether the stomata are open or closed?
light intensity
What 3 specialisations are found in most plants to reduce water loss?
waxy cuticle, stomata on underside of leaf, wilting
What is measured using a potometer?
Rate of water uptake / transpiration in a plant.
What are appropriate units to use for calculating the rate of transpiration using a potometer?
mm / min
What are 3 uses of water in a plant?
Photosynthesis, transport, keeping plant upright
What is glucose converted into for it to be transported in a plant?
Sucrose
What process transports sucrose through the phloem vessels?
Translocation (it requires energy from respiration)
What is a source in a plant?
A part of the plant that produces sugars.
What is a sink in a plant?
A part of the plant that requires sugars and cannot produce it themselves.
Where is the source in a plant during the summer?
Leaves
Where is the source in a plant during the spring?
Roots
Where is the sink in a plant during the summer?
Roots
Where is the sink in a plant during the spring?
Growing leaves
What are sugars stored as in the roots?
Starch
What process loads sucrose into the phloem vessels at the source?
Active transport
What process unloads sucrose from the phloem vessels at the sink?
Diffusion
What causes sucrose to flow in the phloem vessels from the source to the sink?
Difference in pressure / pressure gradient
