This lab focuses on:
- Investigation the processes of diffusion and osmosis in a model membrane system
- Investigating the effect of a solute concentration on water potential as it relates to living plant tissues
For this lab you must understand:
- Mechanisms of diffusion and osmosis and their role in cells
- The effects of solute size and concentration gradients on diffusion across selectively permeable membranes
- The effects of a selectively permeable membrane on osmosis and diffusion between two solutions separated by the membrane
- The concept of water potential
- The relationship between solute concentration and pressure and the water potential of a solution
- The concept of molarity and its relationship to osmotic concentration
Properties of water potential will be useful in this lab
- Water moves across a selectively permeable membrane from an area of higher water potential to an area of lower water potential
- Water potential can be positive or negative.
- Solute potentials result from the presence of solutes and are always negative. The higher the concentration of solutes the smaller, or more negative, the pressure is.
- Pressure potential is zero unless some force is applied, like that applied by a cell wall
- Pure water at atmospheric pressure has a water potential of zero