Movement Of Substances Flashcards
What does selectively permeable mean?
Allows some substances to pass through but not all
Give an example of semi-permeable membrane
Cell membrane
Advantages of being semipermeable
Nutrients [O2 H2O] can enter freely
What is diffusion?
Movement of substances from high concentration to low concentration
What is osmosis?
Movement of water from high water concentration to low concentration across selectively permeable membrane
What happen in osmosis in animal cells when fresh water
Water enters by osmosis,cells swell and may burst
What happens to osmosis in animal cells in high solute water [salt]
Water leaves by osmosis, cells shrivel and die
What happens to osmosis in plant cells in fresh water
Water enters the cells by osmosis, cell water prevents bursting, cell wall becomes turgid/has high turgor pressure
What happened to osmosis in plant cells in high solutes solution [salt]
Water leaves the cell by osmosis, cell shrivels, cell becomes plasmolysed /has low turgor pressure
What is turgor pressure?
Pressure of cell contents against cell wall
What is plasmolysis?
Loss of water from the vacuole and cytoplasm and movement of cell membrane await away from cell wall
Why can’t animal cells be turgid?
No cell wall
Why lack of turgidity is not problematic for animals
Have a skeleton for support
Where is osmosis in preserving food?
Meat/fish is stored in salty solution
Jams/marmalades have high sugar contents
-microorganisms lose water by osmosis and shrivel and die
What is active transport?
Movement of substance from low concentration to high concentration
