Diffusion & Osmosis Flashcards
Osmosis
Movement of waterfrom a high water to a low water concentration through a semi-permeable membrane.
Why is osmosis special
Passive- requires no energy.
Diffusion
The movement of molecules from an area of high to low concentration. Passive.
Selectively permeable membranes
Allow some but not all substances through.
Permeable
Lets substances through
Impermeable
Substances cannot pass through.
Solvent
A liquid eg water that dissolves other substances.
Solute
A substance that has been dissolved.
Solution
A mixture of solute + solvent. Salt water.
How do amoeba survive in freshwater (less concentrated environments?
Bc the contractile vacuole eliminates water.
Animal cells stay the same size in?
A solution with the same concentration as their cytoplasm.
Animal cells swell and burst in
Less concentrated solution.
Animal cells shrivel and die + lose water in
A solution more concentrated than their cytoplasm.
Plant cells in a solution less concentrated than their cytoplasm
Gain water, become turgid and strong.
Plant cells in a more concentrated solution than their cytoplasm
Lose water and become weak.
High salt and sugar concentration
Used to remove water from micro-organisms by osmosis.
Used in food preservation.
Experiment
Pg 152
Active transport
Movement of molecules from a less to a more crowded area.
Uses energy.
Hypertonic animal cell
Water leaves cell, shrivels.
Isotonic animal cell
Ideal, water comes in and out.
Hypotonic
Water comes into cell. Overinflated.
Turgor pressure
The outward pressure of the cytoplasm and vacuole against the cell wall of a plant.
Plasmolysis
The movement of the cell membrane away from the cell wall.
