Plant Water Absorption and Cellular Transport Processes

Absorption by the Roots

Key Biological Definitions

1. Imbibition: It is the phenomenon by which a living or a dead cell absorbs water through surface attraction.
2. Diffusion: It is the free movement of molecules of a substance from a region of higher concentration to lower concentration when the two are in direct contact.
3. Osmosis: It is the process of movement of water molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.
4. Endosmosis: It is the inward diffusion of water through a semi-permeable membrane when the surrounding solution is less concentrated.
5. Exosmosis: It is the outward diffusion of water through a semi-permeable membrane when the surrounding solution is more concentrated.
6. Osmotic Pressure: The osmotic pressure of a solution is a measure of its tendency to take in water by osmosis.
7. Tonicity: Relative concentration of the solutions that determine the direction and extent of diffusion.
8. Isotonic: The relative concentration of water molecules and the solute on either side of the cell membrane is the same.
9. Hypotonic: The solution outside the cell has a lower solute concentration than the fluids inside the cell.
10. Hypertonic: The solution outside the cell has a higher solute concentration than the fluid inside the cell.
11. Active Transport: It is the passage of a substance from its lower to higher concentration through a living cell membrane using energy from the cell.
12. Passive Transport: Free movement of molecules from a region of higher concentration to a region of lower concentration.
13. Turgor Pressure: The pressure of the cell contents on the cell wall is called turgor pressure.
14. Wall Pressure: Pressure exerted by the cell wall on the cell contents is called wall pressure.
15. Turgidity: It is the state of a cell in which the cell wall is rigid and stretched by an increase in the volume of the vacuole due to the absorption of water.
16. Plasmolysis: It is the contraction of cytoplasm from the cell wall caused by the withdrawal of water when placed in a strong solution.
17. Flaccidity: The condition of being soft and limp, occurring when water leaves the cell and the cell is no longer turgid.