full explanation on diffusion and osmosis of class 9

1. Diffusion and
Osmosis
BY KASHISH

2. INTRODUCTION
O cell membrane allows only selected
substances to move through it
O the movement of substances takes place
by activities like :diffusion & osmosis

3. O “Movement of
molecules from
higher
concentration to
lower
concentration”
O it is mostly seen in
gases
O ex: cell respire i.e
intake of 02 & giving
out co2 take place
through diffusion

4. diffusion in particles

5. O

7. O “the solution that has higher water
concentration”
O this solution is very dilute, the cell will gain
water by osmosis
O in this situation, cell is likely to swell up i.e
become inflated or turgid
O this is also called endosmosis

9. O when the cell is placed in isotonic
solution, which has excatly the same
water concentration as the cell
O there will be no net movement of water
molecules across the cell membrane
O although water passes cell membrane in
both directions , the amount of coming in
is the same as going out
O therefore, cell remain in the same size

11. O when the cell is immersed in (very
concntrated) hypertonic solution , water
will diffuse out of the cell by osmosis
O although water passes through both the
direction more water goes out of the cell
O As a result, the cell will shrink
O this process is also called as exosmosis
O if exosmosis continue in plant cell the
cytoplasm would appear shrunken
O this is called plasmolysis and cell is said to be
plasmolysed

19. ACTIVE/PASSIVE
TRANSPORT

20. ex: of active transport are
endcytosis and exocytosis