Transport in Vascular Plants Flashcards
what is transported?
water
nutrients
sugar
hormones
why are water plants better for transport?
water is everywhere so provides everything except sugars
how do the roots work?
absorb water and nutrients from soil, specifically damp, nutrient rich soil
synthesis the correct proteins for absorption
respond to water/nutrient need
competition - distinguish between self and non self
what do roots need?
bulk flow at high pressure from roots to leaves at low pressure
difference between diffusion and active transport?
active needs energy and is low to high
diffusion passive and is high to low
what is water potential?
flow from high to low
what is pressure potential?
water pushing against sides in plants promoting tension so plant stiff
loss leads to wilting
what happens to solute potential when high solute conc?
lowers
water potential =
solute potential + pressure potential
what are secondary metabolites?
defences usually chemical that deter herbivores, plants focus investment on toxins
why are secondary metabolites necessary?
plants need to defend themselves as can’t run away
what is automimicry?
when the herbivore overcomes toxin and can use it itself
how do monarch butterflies feed on something other than milkweed?
learned aversion - but frequenty dependent
how is water pulled up a plant?
against gravity due to difference in water pressure in leaves and rest of plant
cohesion of water and adhesion of xylen walls also helps
what is the function of the xylem?
takes water from roots to leaves
how does the xylem carry so much water?
secondary growth increases capacity of trunk and stems
what is the function of the stomata?
minimising water loss
controlled by guard cells
factors that affect opening/closing of stomata?
light, time, hormones when soil moisture low, wind
function of the phloem?
carrys sugars up the plant - for respiration, storage, growth
bulk flow doesn’t require energy but active transport does to load sap into carbs
how does the phloem work?
pressure driven, low at sinks, high at sources
what is contained in sap and where is it found?
Phloem
amino acids, nutrients, glucose, hormones
