5.5 Osmosis Flashcards
Solute definition
a substance dissolved in a solvent forming a solution
Water potential definition
pressure exerted by water molecules as they collide with a membrane or container
–> units: pascals Pa or kPa
–> symbol is psi
Water potential of pure water
0kPa at standard temp and atmospheric pressure)
–> highest possible value as presence of solute in water lowers the water potential below 0
–> all solutions have negative water potentials
Osmosis definition
the diffusion of water molecules from high water potential to low water potential across a partially permeable membrane
Hydrostatic pressure
pressure exerted by any liquid in a closed space upon the walls of the container
Movement of water from high water potential to low water potential is the same as??
dilute solution to concentrated solution
or
low conc of solute to high conc of solute
Cytolysis
bursting of a cell due to an increased hydrostatic pressure within a cell
–> the thin cell surface membranes cannot stretch and withstand the force
What happens when an animal cell is placed in a hypotonic solution?
Hypotonic= higher water potential than cytoplasm (less negative)
–> water moves into the cell, causing it to swell and burst
What happens when an animal cell is placed in a isotonic solution?
Isotonic= exact same water potential as the cytoplasm
–> water leaves and enters at the same rate= no change
What happens when an animal cell is placed in a hypertonic solution?
Hypertonic= lower water potential than cytoplasm (more negative)
–> water moves out of the cell, causing it to shrink and crenate
–>reduction in cell volume
What adaption allows plants to withstand more pressure than animal cells
strong cellulose walls that can resist the turgor pressure
What happens when a plant cell is placed in a hypotonic solution?
Hypotonic= higher water potential than cytoplasm (less negative)
–> water moves into the cell, causing it to swell and become turgid
–> protoplast pushed against cell wall
What happens when a plant cell is placed in a isotonic solution?
Isotonic= exact same water potential as the cytoplasm
–> water leaves and enters at the same rate= no change
–> protoplast beginning to pull away from cell wall
What happens when a plant cell is placed in a hypertonic solution?
Hypertonic= lower water potential than cytoplasm (more negative)
–> water moves out of the cell, causing it to shrink and plasmolysis
–> protoplast completely pulled away from cell wall
–> extra space is filled with external solution of lower water potential
