Passive transport allows substances to cross the cell membrane without expending energy. There are three main types of passive transport: diffusion, osmosis, and facilitated diffusion. Diffusion is the movement of molecules from an area of high concentration to low concentration. Osmosis is the diffusion of water across the cell membrane and is dependent on solute concentrations inside and outside the cell. Facilitated diffusion uses carrier and channel proteins to transport molecules that cannot diffuse directly through the membrane down their concentration gradient.

1. PASSIVE TRANSPORT BY – M.NAFLY Biomedical scientist * Nafly Hussain * Biomedical science *

3. Osmosis

4. Facilitated Diffusion* Nafly Hussain * Biomedical science *

5. Diffusion * Nafly Hussain * Biomedical science *

6. Diffusion molecules of a substance will move from an area of high concentration to an area of low concentration. Diffusion occurs in cells when substances Small & uncharged molecules like O2,CO2, salts, sugars & amino acids . that are dissolved in H2O move from an area of higher concentration to an area of lower concentration. * Nafly Hussain * Biomedical science *

7. Osmosis Osmosis is the diffusion of water across the cell membrane. The direction of osmosis depends on the concentration of solutes inside and outside the cell. * Nafly Hussain * Biomedical science *

9. Hypotonic -concentration of solutes outside the cell is lower than the concentration inside. Water will move into the cell to create equilibrium.

10. Hypertonic -concentration outside the cell is higher than inside. Water will move out of the cell to create equilibrium.

11. equilibrium -all molecules occupy the same amount of space* Nafly Hussain * Biomedical science *

12. Osmosis Effects on Cells * Nafly Hussain * Biomedical science *

13. Facilitated Diffusion * Nafly Hussain * Biomedical science *

14. Facilitated Diffusion This process is used for molecules that can’t move quickly through the cell membrane. Carrier proteins help move the molecules. The molecules still move down the concentration gradient so no energy is required. Transport of glucose is facilitated diffusion. Carrier proteins - Transports non-charged molecules with a specific shape. Channel proteins - Tunnel shape that transports small charged molecules. * Nafly Hussain * Biomedical science *

15. Channel proteins & Carrier proteins * Nafly Hussain * Biomedical science *

16. The end * Nafly Hussain * Biomedical science *