Absorption Of Roots Flashcards
What is adhesive Force?
It is the force between the capillary wall and water
What is Cohesive Force?
It is the molecular attraction by which the particles of the body are united throughout the mass.
Specify characteristics of root hair for absorbing water:
- Large surface area
- The Cell sap concentration inside the root hair is more compared to outside the cell.
- They have thin walls.
What is Imbibition?
The process of water absorption by hydrophilic substances that may be living or dead. Cellulose and protein have great affinity for water.
Define Defusion.
Diffusion is defined as the free movement of molecules from a region of their higher concentration to their lower concentration when they are in direct contact.
Define Osmosis.
Osmosis is the movement of water molecules from a region of its higher concentration to a region of its lower concentration through a semi-permeable membrane.
What is endosmosis and exosmosis?
Endosmosis: the inward movement of water through a semi-permeable membrane.
Exosmosis: the outward diffusion of water through a semi-permeable membrane when surrounding solution is more concentrated. This causes shrinkage of cell.
Name a few semi-permeable membranes
Egg Membrane, Animal Bladder and Cellophane Paper.
Is Muslin Cloth freely permeable?
Yes
What are the three degrees of tonicity?
- Isotonic: the concentration of water inside and outside the cell is same, no movement. Cell Shape and size remains same
- Hypotonic: the concentration of water inside the cell is less, leading to endosmosis. Cell loses shape and shrinks in size.
- Hypertonic: the concentration of water inside the cell is more, leading exosmosis. Cell enlarges and may burst.
What is Turgidity?
It 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.
What is Plasmolysis?
It is the contraction of cytoplasm from the cell wall caused due to withdrawal of water when placed in a strong (hypertonic) solution.
When a cell is plasmolysed what is term for the condition and also state what is the reversal of Plasmolysis:
The condition in which a cell shrinks (during Plasmolysis) is called Flaccid. Flaccidity is the reversal of turgidity.
The reversal of Plasmolysis is called De-Plasmolysis.
Define Flaccidity.
It is the state of cell when the cell has shrunk due to loss of water and it no more tight.
Define. active Transport:
Active transport is defined as the passage of substances (salts or iron) opposite to the concentration gradient (lower to higher) through a living cell membrane using energy from the cell.
