1. Cell Transport Movement of substances in and out of cells

2. Substances move in and out of cells by:
Passive Transport
Active Transport

3. Passive Transport
No energy (ATP) is required to move gas or liquid molecules from one place to another!
(Is this an example of a “free lunch” or perpetual motion?… imagine if our cars worked like this….)
Need to understand concepts of :
Diffusion,
Osmosis,
Concentration gradient,
Net movement

4. Diffusion
The random movement of molecules from an area of high concentration to an area of low concentration.
Down the concentration gradient.
Conc. Grad

5. Rate (speed) of diffusion depends on:
fast slow
Size of molecules
Temperature
State of matter
Concentration gradient

6. Osmosis
Net movement of water molecules from an area of high water concentration to an area of low water concentration, through a semi-permeable membrane.
Hypertonic – more solute and less water
Hypotonic – less solute and more water
Isotonic – same conc. of solute and water

7. Think (don’t write) Most marine fish die if transferred to freshwater.
When a drop of blood is mixed with distilled water, the blood cells burst.
Living plant tissues that had lost water become firm when supplied with water.

8. Net movement
The overall movement of all molecules of a substance back and forward along the concentration gradient.
e.g. when oxygen or water molecules diffuse into a cell, some molecules move out at the same time. Overall more are moving inwards than outwards so the net movement is………..

9. Osmoregulation The control of water in a cell. Plasmolysis –
Water leaves cell and membrane shrinks from wall.
Cell becomes flaccid.
Full plasmolysis is irreversible.

10. Turgor Water enters cell causing it to swell Cell becomes turgid
Cell wall prevents rupture

11. Active Transport Energy (ATP) is required for:
Endocytosis (phago- and pino-),
Exocytosis,
Ion pumps
e.g. re-absorption of glucose by kidney, salt uptake by the roots of plants, amino acid uptake by fungi

12. Against the concentration gradient
The movement of substances from an area of low concentration to an area of high concentration.
Against the concentration gradient
Conc. Grad

13. Cytosis 1.Endocytosis Movement in (enter) to a cell
Phagocytosis – cell eating – forms a food vacuole.
e.g. Lysosomes fuse to enable digestion.
Pinocytosis – cell drinking – forms a vesicle
e.g. Amoeba and white blood cells (WBC) – pseudopodia

14. 2.Exocytosis Movement out (exit)
Vesicles bud off from golgi apparatus or ER, vacuole fuses with cell membrane and expels contents
Secretions e.g. digestive enzymes released, glands

15. Ion Pumps
Proteins in the cell membrane can actively accumulate specific ions on one side of the membrane to control the amount