Definitions [10]
Diffusion is the free movement of molecules of a substance (solute or solvent, gas, liquid) from the region of their higher concentration to the region of their lower concentration when the two are in a direct contact.
Define diffusion.
Diffusion is the free movement of molecules of a substance (solute or solvent, gas, or liquid) from the region of their higher concentration to the region of their lower concentration when the two are in direct contact.
Example: Perfume fills a whole room.
Define the following term:
Active transport
Active transport is the passage of a substance (salt or ion) from its lower to higher concentration through a living cell membrane using energy from the cell. Active transport is in a direction opposite to that of diffusion.
Active transport is the passage of a substance (salt or ion) from its lower to higher concentration through a living cell membrane using energy from the cell. [Active transport is in a direction opposite to that of diffusion.]
The pressure of the cell contents on the cell wall is called turgor pressure.
Plasmolysis is the process in which the cytoplasm shrinks and the plasma membrane pulls away from the cell wall due to the loss of water when a plant cell is placed in a concentrated solution.
or
Plasmolysis is the contraction of cytoplasm from the cell wall caused due to the withdrawal of water when placed in a strong (hypertonic) solution.
Flaccidity is the condition of a cell when it becomes limp due to plasmolysis, and the plasma membrane is no longer pressed tightly against the cell wall. It is the reverse of turgidity.
or
Flaccidity is the condition in which the cell content is shrunken and the cell is no more "tight'. The cell is then said to be flaccid.
Turgidity is the condition in which a cell becomes fully swollen with water, exerting pressure on the cell wall.
or
Turgidity is the state of a cell in which the cell wall is rigid and stretched by an increase in the volume of vacuoles due to the absorption of water. The cell is then said to be turgid.
A cell is said to be turgid when it is fully distended by the maximum intake of water and can no longer accommodate more water.
The pressure exerted by the cell wall on the cell content is called wall pressure.
Concepts [12]
- Introduction of Transport in Plants
- Movement of Water, Gases and Nutrients
- Cell to Cell Transport
- Diffusion
- Active Transport
- Osmosis
- Turgidity and Flaccidity (Plasmolysis)
- Introduction of Long Distance Transport of Water
- Uptake of Mineral Ions
- Concept of Plant-water Relations
- Diffusion of Gases
- Transport in Plants (Numericals)
