NOTES & NCERT Flashcards
types of transport in short distance transport
diffusion
facilitated diffusion
active transport
long distance transport is called
translocation
translocation takes place through
vascular system - xylem and phloem
classify water, food, minerals and plant hormones on the basis of dxn and as organic/inorganic
water - inorganic, unidirectional
food - organic, bidirectional
minerals - organic & inorganic, some uni some bi
plant hormones - unidirectional
diffusion
dxn? concentration and diffusion pressure?
enegy?
protien? related aspects?
high to low concentration & high DP to low DP
no energy
no protien - no transport saturation, not specific, not sensitive to inhibitors
why is diffusion very important to plants
diffusion is the only means of gaseous movement within the plant body
factors affecting diffusion
concentration gradient
permeability of membrane
temprature & pressure
facilitated diffusion
process?
dxn?
energy?
protein? related aspects?
hydrophilic molecules are transported across the membrane through carrier proteins
high to low concentration
no energy
protein required - ✓transport saturation
✓specific and ✓sensitive to inhibitors
transport saturation
transport rate reaches max when all the protein transporters are being used
in facilitated diffusion, proteins form ___ in the membrane for molecules to pass through
channels
porins
location
huge protein pores - allow small (protein sized) molecules to pass
outer membranes of plastids, mitochondria and some bacteria
water channels
made of 8 different types of aquaporins
uniport
symport
antiport
molecules move across the membrane independent of other molecules
two molecules cross the membrane in same dxn
two molecules cross the membrane in different dxn
active transport
dxn?
energy?
protein? related aspects?
lower to higher concentration
energy required
proteins required - ✓transport saturation ✓specific ✓sensitive to inhibitors
whats are pumps in active transport
proteins that use energy to carry substances across the cell membrane - uphill
active transport is carried out by ___ proteins
membrane proteins
___ and ___ types of transport are under hormone regulation
facilitated diffusion and active transport
imbibition?
eg?
water movement is along?
special type of diffusion where water is absorbed by solids or colloids causing them to enormously increase in volume
absorption of water by seeds or dry wood
water movement is along concentration gradient
due to imbibition pressure only
seeds are able to emerge out of the soil
bulk or mass flow
the movement of substances in bulk from one point to another due to pressure difference btw the two points
bulk flow can be achieved through ___ or ___
+ve hydrostatic pressure gradient
-ve hydrostatic pressure gradient
materials translocated through xylem and phloem
xylem - water, mineral salts, organic N, hormones from roots to areal parts of the plants
phloem - organic and inorganic solutes mainly from leaves through other plant parts
root hairs
slender extensions of root epidermal cells
explain root hair to xylem water flow
root hair to root - diffusion along with mineral solutes
root to xylem:
⚫apoplast pathway -
⬛through intercellular spaces and cell walls
⬛most water flow takes place as cortical cells are loosely packed and so offer no resistance to water
⬛due to the presence of casparian strip (band of suberised matrix) at the endodermis wall the water is directed into the endodermis
⬛in young roots water enters directly into xylem vessels and trachieds. These are non living conduits and so are parts of the apoplast
⚫symplast pathway -
⬛system of interconnected protoplast connect through cytoplasmic strands extended through plasmodesmata
⬛aided by cytoplasmic streaming (eg: in hydrilla leaf)
in young roots water enters directly into xylem vessels and trachieds
