osmosis Flashcards
osmosis defenition
net diffusion of water mols across a selectivley permable membrane from a region of higher water potential to a region of lower water potential
water potential defeinition
tendency for water to move into a system
from higher water potential (less negative) to lower water potential (more negative)
how is water potential decreased
by addition of solute
what is the water potential of pure water
zero
what unit is water potential measured in
kilopascals (kPa)
what does addition of solute do to water potential
bring water molecules in, gives it a negative value
explination of osmotic pull
external water molecules with higher potential energy move down an energy graident to the lower
defnition of solute potential
measure of osmorux strength of solution
it is the reduction in water potential due to the presence of solute molecules
defnition of turgid
plant cell that holds as much water as possible
further entry of water is prevented as cell wall cannot further expand
what is the name of the pressure when the cell is turgid
pressure potential
what does osmosis expand in plant cell
vacuole
pushes cytoplasm against cell wall
what are the 2 opposing forces in plant cells
solute potential
pressure potential
solute potential in plant cells
solutes in vacuole and cytoplasm pulling water in
higher they are, less likely water is to move out
dumb expliantion of what water potential is
force which increases the water potential of the cell and whether water moves in or out
water potential equation
pressure potential + solute potential
what does it mean if the external solution is hypotonic
water flows into the cell
what does it mean if the external solution is hypertonic
water flows out of the cell
why does hypotonic external solution occur
water potential of external solutiono is higher than solution inside the cell
why does hypertonic external solution occur
water potential of external solution is lower than the solution inside the cell
what will happen if the external cell solution is isotonic
no net water movement
why does isotonic external solution occur
cell has same water potential as external solution
whats the cell called when plasmolysis happens
flaccid
what happens to the plant when its cells are flacid
cells cannot provide suppport
what is the pressure potential during incipient plasmolysis
no pressure potential as the cell wall doesnt put pressure on cytoplasm
when does hypotnic solution stop taking in water?
until prevented by the opposing pressure from the cell wall
defenition of plasmolysis
retraction of the cytoplasm and the cell membrane from the cell wall as a cell looses water by osmosis
defenition of incipient plasmolysis
cell membrane annd cytoplasm are partially detatched from the cell wall due to insufficient water to make cell turgid
what is the name of the cell when it can no longer take water in
turgid
why is turgor important
provides support, maintains shape and hold young seedlings upright
cytoplasm location in turgid cell
cytoplasm pushed against cell wall
cytoplasm location in incipient plasmolysis cell
cytoplasm begining to pull away from cell wall
cytoplasm location in plasmolysed cell
cytoplasm completley pulled away from cell wall
why does pressure potential not have to be considered in animal cells
they dont have cell walls
technical term for if red blood cells absorb too much water without wall they burst
haemolysis
technical term for cells shriveling
crenated
what version of water potential would shrivel
hypertonic
what version of water potential would swell
hypotonic
