•Osmosis – movement of water across a membrane from high to low concentrations
•This is a type of diffusion:
–Which is a movement of molecules from high to low concentrations.
•Hypertonic Solutions: –Solution where there is a higher amount of solute outside the cell or a lower amount of water outside the cell.
•Hypotonic – solution where there is less solute outside the cell or more water outside the cell.
•Isotonic Solution – solution where the amount of water and solute are equal on both sides of the cell membrane.
•As the Surface Area and Volume of a cell increase their Surface Area to Volume ratio decreases because the cell has less surface area to allow for diffusion of nutrients inside the cell. This smaller Surface Area to volume to ration that arises from cells becoming larger limits cell size because the cell can not take in nutrients or expel wastes through diffusion very efficiently because it takes longer.
Cells in hypertonic solutions shrink due to movement of water out of then.
Cells in hypotonic solutions swell due to water movement into them.
Cells in isotonic solutions do not change because water is at equilibrium in and out of the cell.
As a cell becomes larger the speed of diffusion decreases for the cell.
As a cell becomes large its Surface Area to Volume ratio becomes smaller, thus the cell has more volume than surface area for diffusion.
As surface area to volume ration decreases the rate of diffusion decreases.
