2.4.3 Osmosis

1. 2.4.3 Osmosis

2. Osmosis • Movement of water molecules from a high concentrated area (dilute solution) to a low concentrated area (concentrated solution) through a semi permeable membrane. It is diffusion of water.

3. Protein molecule Water molecule Semi permeable membrane Outside the leaf Inside the Leaf Steps in Osmosis Where is water more? Inside or outside the cell? Water will also diffuse from where it is more to where it is less. Therefore when water is more outside than inside the cell, it will move inside It can also move out of the cell if there is more water inside the Than outside

4. Osmosis continued Salt water Outside the leaf Inside the Leaf Now you placed this leaf in Salt solution. What would happen To the water?

5. This is what cells would look like in different conditions: Plant cell • When water moves out of cell: http://www.youtube.com/watch?v=qucTUoHAeuY&feature=related http://www.youtube.com/watch?v=gWkcFU-hHUk http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

6. Plant and animal cell

7. Importance of water potential gradient • Where there are free water molecules – this is where the water potential is high (because it is able to move freely) • Concentrated solutions have low water potential • Dilute solutions have high water potential • Osmosis: the net diffusion of water molecules from a region of high water potential to a region of low water potential through a partially permeable membrane.