| A | B |
|---|
| Diffusion is the the movement of particles of a substance | from a region where they are in higher concentration to a region where they are in lower concentration. |
| Osmosis is the | movement of molecules of water from a region of their higher concentration to a region of their lower concentration through a partially permeable membrane. |
| A partially permeable membrane | allows the particles of some substances to go through but not others. |
| diffusion occurs fastest in | gases |
| Diffusion occurs slowest in | solids. |
| accounts for the absorption of water | The process of osmosis |
| account for the absorption of dissolved mineral salts. | The processes of diffusion and active transport |
| Active transport is the movement of particles of a substance | from a region of their lower concentration to a region of their higher concentration using energy. |
| root hairs | tiny, finger-like outgrowths from cells in the epidermis of the root |
| root hairs | provide a very large surface area for the absorption of water and dissolved mineral salts |
| Odour from rubbish heaps reach us by the process of | diffusion. |
| The process of diffusion accounts for | the gaseous exchange between an organism and its surroundings. |
| Plasmolysis can occur when | cells are put in concentrated salt solutions. |
| permeable membrane | allows free diffusion of substances |
| Carbon dioxide diffuses out of the bloodstream | into the alveoli of our lungs. |
| Oxygen diffuses from the alveoli of our lungs | into the blood flowing through the blood capillaries lining the wall of the alveoli. |
| visking tubing and cellophane | examples of non-living partially permeable membranes |
| Water molecules can move | from a dilute solution to a concentrated solution when they are separated by a partially permeable membrane. |
| A dilute solution has a higher concentration of water molecules than | a concentrated solution. |
| Animal cells will burst | if too much water enters. |
| Plant cells will not burst | with the entry of water because of the presence of a strong, rigid cell wall. |
| As a plant cell loses water | the vacuole shrinks and the contents of the cell pulls away from the cell wall. |
| A plant cell becomes turgid | as water enters. |
| A plant cell becomes flaccid | as water leaves. |
| A plant wilts when there is | excessive loss of water. |
| Active transport accounts for | the absorption of dissolved mineral salts when the soil water has a higher concentration of them than the cell contents of root hair cells. |
| A slice of cucumber placed in concentrated sugar solution will | turn flaccid. |
| A slice of cucumber placed in distilled will | turn turgid. |
