Wednesday, 19 September 2018

CBSE Class 9 - Cell Biology - 7 Points about Plasmolysis (#cbsenotes)(#eduvictors)

Cell Biology - 7 Points about Plasmolysis


Plasmolysis vs Flaccid vs Turgid
Credits: Wikimedia, Author: LadyOfHats

1. When a living plant cell loses water through osmosis there is shrinkage or contraction of the contents of the cell away from the cell wall. This phenomenon is known as plasmolysis
(plasma → fluid; lysis → disintegration, decomposition).


2. Only living cells, and not dead cells, are able to absorb water by osmosis.


3. Cell walls permit the cells of plants, fungi and bacteria to withstand very dilute [hypotonic] external media without shrinkage.




4. In such media, the cells tend to lose water by osmosis. The cell shrinks, building up pressure against the cell wall. The wall exerts an equal pressure against the shrunken cell.


5. Cell wall also prevents the bursting of cells when the cells are surrounded by a hypertonic medium (medium of high concentration).


6. In such media, the cells tend to gain water by osmosis. The cell swells, building up pressure against the cell wall. The wall exerts an equal pressure against the swollen cell.


7. Because of their walls, plant cells can withstand much greater changes in the surrounding medium than animal cells.


☛See also:
Ch 5 - Fundamental Unit of Life (Q & A)
Ch5 - Fundamental Unit of Life (MCQs)
Ch5 - Fundamental Unit Of Life (Question Bank)
Ch5 - Fundamental Unit Of Life - Quiz On Cell Organelles
Ch 5 - Interactive Cell - Play to learn about cell organelles
Ch5 - Fundamental Unit of Life (Worksheet)
Ch5 - 7 Points About Plasmolysis