Topic F- Plant Transport Flashcards
Adaptations of a root hair cell
covered in millions of hairs= big SA
large surface area= exchange of particles can happen quickly ( osmosis, diffusion, active transport)
lots of mitochondria for energy ( ATP) for active transport
How is water absorbed by the root hair cell
Osmosis
- water potential = inside + outside cell therefore no movement osmosis )
- cell does active transport of mineral ions
- mineral ions concentration goes up inside cell = decrease water potential inside = increase of water potential inside
- therefore water moves by osmosis down the water potential gradient into the cell
- until equilibrium is reached ( back at the beginning )
- volume in cell increases = pressure increasing= process happening in next cell along
adaptations of xylem
thick walls of lignin= waterproof/ stop cell collapsing
dead cells= no cytoplasm/organelles= no obstruction to water flow
what does the xylem transport and from where 2 where
transports - water and mineral ions
one way flow from the root to leaf
travels up the xylem by transpiration pull
definition of transpiration pull/ stream
when water is drawn up the xylem vessel to replace water loss at the leaves
adaptations of phloem
alive cells + thin cytoplasm = so sugar transport doesn’t stop
no nucleus/organelles ( but in companion cell ) = reduces resistance of sugar flow
companion cell= controls everything
sieve plates = control which direction sugar goes in ( movement of substances )
what does the phloem transport and from where 2 where
transports- sucrose + amino acids (food)
2 way flow = from source ( where made) 2 sink ( where used )
between the leaves and other parts of the plant
definition of transpiration
evaporation of water from surface of a plant
when water vapour diffuses into through the stomata from the leaf lowering the water potential inside the leaf
what happens in the leaf ( in terms f water transport and gasses )
xylem = gets water into leaf - which diffuses round in air spaces
water uses = photosynthesis
keeps cell turgid- supports the plant
most goes out of the stomata
guard cells = close at night- no CO2
open in day - water + CO2 in 4 photosynthesis
what 4 factors affect rate of transpiration
- Humidity
- Wind speed
- Temperature
- Light Intensity
how does humidity affect transpiration
increase in humidity ( water potential outside increases) = decrease in transpiration ( cos of reduction in concentration gradient )
how does wind speed affect transpiration
increase wind speed = increase transpiration
wind removes H2O outside leaf= increases concentration gradient
how does temperature affect transpiration
heat = H2O molecule has more energy= moves faster= more evaporation = increase transpiration rate
how does light intensity affect transpiration
increase light= open pore width ( at night stomata closes )= more space = more evaporation= increase transpiration
Describe the transpiration rate experiment
- cut the end of stem diagonally in the water (so no air enter xylem)
- put potometer tube in water and remove all air bubbles
- connect the stem and photometer under the water and make sure form water tight junction
- Do not get any of the leaves wet ( so water can enter through stomata )
- remove connected tube and stem from water + leave bit of tube hanging in water and mark 10cm on tube
- taking hanging bit of tube in water out and block end to create air bubble
- time how long it takes for air bubble travel the 10cm
- the divide distance/ time giving u the rate
- repeat and take an average
