TRANSPORT IN PLANTS Flashcards
Types of transport
Diffusion facilitated diffusion active transport
diffusion
molecules move from high concentration to low concentration
diffusing particles create a pressure called
diffusion pressure
how is diffusion important in plants
only form of transport for gaseous molecules in plant
Diffusion depends on
concentration gradient membrane permeability temperature pressure size of substance (smaller substance diffuse faster)
facilitated diffusion
diffusion of hydrophilic substances along concentration gradient through fixed membrane proteins
why cant facilitated diffusion cause net movements of particles
because it requires energy
when is facilitated diffusion said to be saturated
when all transporter proteins are being used
membrane proteins for facilitated diffusion are very specific TRUE OR FALSE
TRUE
Porins are ………. that form ……… pores in the outer membrane of ……….. , ……….. , ………… all allow ……….. size proteins to pass through
proteins large chloroplast mitochondira bacteria small
water channels are made of how many aquaporins
8
types of facilitated diffusion
uniport symport antiport
active tranport
movement of substances agaisnt the concentration gradient by using ATP
What are pumps
proteins that transport substances against concentration gradient (uphill transport)
saturation effect
all pumps are being used
movement of transport proteins is done by
active transport
what forms of transport respond to inhibitors
facilitated diffusion and active transport
how much % of watermelon is water
92 %
% of dry weight in herbaceous plants
10-15%
corn plant absorbs …… liter of water a day
3
mustard plant can absorb water equal to its own weight in
5 hours
water potential
free energy of water
water moves from (in terms of water potential)
hight water potential to low water potential
unit of water potential
pascal
water potential of pure water at standard temperature
0
define solute potential
decrease in water potential when solute is added to water (-ve)
how does pressure affect water potential
it increases it
at atm pressure water potential is equal to
solute potential
water potential =
pressure potential + solute potential
plant vacuole contains
vacuolar sap
what 2 membranes play an important role in movement of water in and out of the cell
cell membrane and tonoplast
osmosis
movement of solvent particles along the concentration gradient through a semi permeable membrane
osmosis is driven by 2 factors
pressure gradient
concentration gradient
osmotic pressure
pressure required to stop osmosis
osmotic pressure relation with osmotic potential (solute potential)
numerically equal
OP is +ve
SP is -ve
factors effecting osmotic pressure
concentration of solute
ionization of solute
hydration of solute particles
temperature
types of sollutions
hypertonic (more solute)
hypotonic (less solute )
isotonic
plasmolysis
withdrawal of protoplasm of the cell due to extensive loss of water
pressure developed by cytoplasm on the cell wall on entry of water
turgor pressure
pressure exerted by protoplast on entry of water on the cell wall
pressure potential
stages of plasmolysis
limiting (TP=0)
incipient (TP= -VE)
evident (TP= —-VE)
imbibition
immobilization of water on the surface of substances
imbibant
imbibate
solid
water
conditions for imbibition
water potential gradient
affintiy between the adsorbent (solid) and imbibed liqued
best imbibant
phycocolloids
diffusion pressure deficit OR suction pressure
terms given by
meyer
renner
what has maximum diffusion pressure
pure water
what happens to diffusion pressure on adding of solutes
it decreases
DPD is
difference in diffusion pressure of pure water and the solution
water moves from (in terms of DPD)
low DPD to high DPD
DPD=
OP-TP
in turgid cell DPD=
0
in turgid cell water potential =
0
translocation
bulk movement of substances through vacular parts of plants
xylem transports
water
mineral ions
organic nitrogen
hormones
different pathways
apoplast pathway
symplast pathway
least resistance in which pathway
apoplast
apoplast blocked by
Casparian strip
symplast pathway
neighboring cells are connected by
plasmodesamata
symplast pathway aided by
cytoplasmic streaming
movement in apoplast due to
transpiration pull
forces of cohesion and adhesion
how much % water abosrbed passivle
96%
water can be absorbed passively when the plant is
transpiring
what pathway does passive absorption take
apoplastic
what pathway does active absorption take
symplastic
how much water is absorbed actively
4%
how does availability of soil water effect absorption
more absorption , if more water
how does soil air effect water absorption
roots require oxygen for development
water logged soil is called PHYSIOLOGICALLY DRY SOIL
how does soil concentraion effect water absorption
highly concentrated soil inhibits absorption
aka PHYSIOLOGICALLY DRY SOIL
Root pressure
active pumping on minerals causes a pressure to develop inside the xylem
+ve
root pressure observed in which plants
herbaceous plants
guttation
loss of water through the hydathodes of the plant due to high root pressure
guttation observed during what part of the day
early morning
and night
root pressure produces a pressure of …………….. causing a rise in
1-2 atm
10-20 m
transpiration pull theory AKA
cohesion tension transpiration pull model
transpiration pull theory introduced by
dixon and jolly
properties of water that aid in its asent
cohesion
adhesion
surface tension
cohesive force AKA
tensile strength
tensile strentgh of water is
10-30 MPa
types of transpiration
stomatal(50-97%)
cuticular(3-10%)
lenticular (0.1%)
bark(1%)
inner wall of gaurd cell
and outer wall of guard cell is
thick and elastic
thin
what aids in stomat opening
radial arangement of cellulose microfibrils
shape of dicot and monocot stomata
kidney shape
dumbelle shape
k malate theory by
Imamura and Fujino gave idea
Levitt explained
explain k malte theory
starch
emp pathwat
PEP
PEPcase
oxalo acetic acid
malic acid
H+ and malate
K+ and Cl- from subsidiary cell
k+ and h+ antiport
kcl and k malate in vacuole
endosmosis
K male theory
at night
PEPcase non funtional as it is light-sensitive
accumulation of co2 in subsidiary cells
activates absisic acid
ABA blocks pump
and K+ and Cl- and water goes back to subsidiary cell
how does light effect transpiration
Blue light causes most opening of stomate
blue and red very effective for opening therefore more transpiration
how does humidity effect transpiration
humid , less transpiration
how does temp effect transpiration
more temp , more transpiration
how does wind effect transpiration
more wind , more transpiration
how does availability of soil water effect transpiration
less water , less transpiration
factors of leaf to prevent transpiration
thick cuticle
sunken stomata
narrow leaves
how does root shoot ration effect transpiration
directly propotional
cobalt chloride test
and jar test
prove
transpiration
significance of transpiration
cooling effect
ascent of sap
maintains cell turgidity
why are minerals activiely absorbed
1) membrane is impermeable to ions
2) higher conc of ions inside the root
example of mobile elements
N,P,K,Mg
examples of immobile elements
Ca, Fe
deficiency of mobile elements first seen in
older parts of plant
deficiency of immobile elements shown in
younger parts of plants
mass flow hypothesis proposed by and elaborated by
munch
graft
girdling experiment by
malphigi
food transported as
sucrose
phloem loading
phloem unloading
phloem enters companion cells actively
phloem leaves leaves the sieve tube actively to the sink
phloem loading casues
drop in water potential and increase in osmotic pressure
food moves ……. to ……….
on girdling what is observed
upper part of girdled region swells up and is filled with nutrients
adventitious roots start growing
