Transport in Stupid Plants Flashcards
Water potential differences _______ water movement
govern the direciton
What is water potential
tendency of a solution to take up water from pure water across a membrane
Equation for water potential?
psi = psi (solute) + psi (pressure)
solute potential is also called
osmotic potential
what is solute potential?
measures the effect of dissolved solutes on the osmotic behavior of the solution
H2O will move wherever the water potential is
less
What is turgor pressure?
The pressure that stops water from coming into the cell as it gets fuller
When the solute and pressure potentials are equal, the cell is
turgid
bulk flow is
flow of higher pressure to lower pressure
Instead of sodium/potassium pumps plants have
proton pumps
How does a proton pump work?
it uses ATP to move protons out of the cell
Describe the apoplast
consists of cell walls and space between them (intercellular space)
Water/substances flow through the apoplast
fast and unregulated
The symplast passes through
the continuous cytoplasm connected by plastmodesmata
Movement through the symlast is _____ regulated
tightly
The endodermis (the innermost layer of the root cortex) is distinguished from the rest of the ground tissue by the
Casparian strip
The Casparaian strip is
a waxy protective layer touching all endodermis cells
T/F: The xylem sap is pumped by living cells
FALSE
Root pressure is
pressure that would force liquid up the xylem
T/F: Root pressure does not account for xylem transport
True
The 3 parts of xylem transport
transpirationcohesiontension
Tension happens when
water evaporates, pulling water up
Transpiration happens when
water vapor leaves from the stomata (concentration of water vapor is less than in the leaf) - causing tension
Cohesion happens when
water moves up together due to hydrogen boding forces (sick)
T/F: Transpiration-tension-cohesion requires energy
FALSE
what does a pressure chamber measure?
tension in xylem sap
Stomata are
the pores that take in CO2 and expel water vapor
Specialized epidermal cells that control opening and closing of stoma
guard cells
Movement through the phloem is called
translocation
A source is
an organ that produces more sugars than it requires
A sink is
an organ that consumes sugars
Cells of the phloem are called
seive tube elements
End walls of plasmodesmata with huge diameters create
seive plates
Cells that conatin seive element organells to direct seive tube elements are called
companion cells
