Osmosis Flashcards
What is osmosis?
-net movement of water from high WP to region of low WP through a partially permeable membrane
Why does osmosis occur in animals?
-losing + gaining water
How does an animal cell lose water?
-if placed in solution with lower WP than cell
-water will leave through memb = shrink (crenation) - could be fatal
-occurs in a hypnotic environment
What is a hypotonic environment?
-solution outside of the cell has higher solute conc than inside
How do animal cells gain water?
-if placed in pure or dilute solution - water will enter - as solution has higher WP
-cell will gain water until it bursts (cytolysis)
-no cell wall to withstand increased pressure created
What happens to an animal cell in isotonic environment?
-outside has the same conc as inside
-no change to cells
Overall statement of osmosis in plant cells
-is less severe - as they have a supporting wall
How do plant cells lose water?
-if placed in solution with lower WP than the cell - water leaves
-as it leaves vacuole - V decreases
-protoplast shrinks - no longer exerting P on wall
-begins to pull away
(Plasmolysis)
How do plant cells gain water?
-if placed in pure or dilute solution
-water enters as it has higher WP than cell
-V increases
-protoplast pushes against wall - inelastic wall prevents bursting
-P stops too much water entering
-when fully inflated = rigid = strength + stand up right to catch sunlight
