Topic 2.8 - Tonicity and Osmoregulation 𖦹⋆｡°✩ Flashcards
how does water move
by osmosis
what is osmosis
the diffusion of free water across a selectively permeable membrane
how do large quantities of water move
via aquaporins
what is osmolarity
the total solute concentration in a solution
does water have high solvency abilities
yes
what is the difference between solutes and solvents
༻ a solute is the substance being dissolved
༻ a solvent is a substance that dissolves a solute
what is a solution
a uniformed mixture of one more more solutes dissolved in a solvent
solvent + solute = ?
solution
what is tonicity
the measurement of the relative concentrations of solute between 2 solutions (inside and outside of the cell)
what does tonicity affect
a cell’s physiology
internal cellular environments can be ____, ____, or ____ to external environments
hypotonic (1) , hypertonic (2) , isotonic (3)
༻ (1) less solute, more solvent
༻ (2) more solute, less solvent
༻ (3) equal concentrations of solute and solvent
where does water move by osmosis
water moves by osmosis into the area with a higher solute concentration
what is the relationship between water and solute concentrations
they are inversely related
how does water move in terms of tonicity
water diffuses out of a hypotonic environment into a hypertonic environment
how do solutes diffuse
along their own concentration gradients, from the hypertonic environment to the hypotonic environment
what happens when a cell is in an isotonic environment
a dynamic equilibrium exists with equal amounts of water moving in and out of the cell at equal rates. no net movement of water takes places
what happens in some plant cells
osmoregulation maintains water balance and allows control of internal solute composition/water potential
what is environmental hypertonicity
less cellular solute and more cellular water
what is an isotonic solution
༻ equal solute and water
༻ flaccid
what is environmental hypotonicity
༻ more cellular solute and less cellular water
༻ turgid
how do osmoregulatory mechanisms contribute to survival
the cell wall helps maintain homeostasis for the plant in environmental hypotonicity
when is osmotic pressure high outside of the plant cell
osmotic pressure high outside of the plant cell due to environmental hypotonicity
what happens when water flows into the plant vacuoles via osmosis
the vacuoles expand and press against the cell wall. the cell wall expands until it begins to exert pressure back on the wall
what is it called when the cell wall expands until it exerts pressure back on the cell
turgor pressure
what is the optimum state for plant cells
turgidity
how does osmoregulation impact animal cells
maintains water balance and allows control of internal solute composition/water potential
what is environmental hypertonicity called in animal cells
shriveled
what is an isotonic solution called in animal cells
normal
what is environmental hypotonicity called in animal cells
lysed
✩REVIEW LAST QUESTIONS FROM VIDEO LESSON✩
what does water potential measure and how is it calculated
the tendency of water to move by osmosis. it is calculated from pressure potential and solute potential
what happens the more negative the water potential is
the more negative the water potential, the more likely water will move into the area
when does water potential have a value of 0
water potential of pure water has a value of 0 in an open container
what does osmoregulation allow organisms to control
༻ their internal solute composition
༻ water potential
what will increasing the amount of solute in water cause
༻ an increase in solute potential
༻ a decrease in water potential
what does increasing water potential cause
༻ an increase in pressure potential
what does decreasing pressure potential will cause
༻ a decrease in water potential
when does water potential equal the solute potential
in an open system (memorize formulae)
what does the addition of solutes do to the solute potential
the addition of solutes is equal to a more negative solute potential
