Diffusion Pressure:

Diffusion pressure refers to the pressure that is created by the movement of molecules from an area of high concentration to an area of low concentration. This movement is called diffusion and it occurs until the concentrations of the molecules are equal throughout the system.

Osmotic Pressure:

Osmotic pressure is the pressure that is generated by the movement of water molecules across a selectively permeable membrane. In other words, osmotic pressure is the pressure that is required to prevent the movement of water molecules from an area of low solute concentration to an area of high solute concentration.

Differences between Diffusion Pressure and Osmotic Pressure:

There are several differences between diffusion pressure and osmotic pressure, including:

1. Movement of molecules
- Diffusion pressure is created by the movement of molecules from an area of high concentration to an area of low concentration.
- Osmotic pressure is created by the movement of water molecules across a selectively permeable membrane.

2. Nature of pressure
- Diffusion pressure is a physical pressure that is created by the movement of molecules.
- Osmotic pressure is a chemical pressure that is created by the concentration of solutes.

3. Direction of movement
- Diffusion pressure causes molecules to move from an area of high concentration to an area of low concentration.
- Osmotic pressure causes water molecules to move from an area of low solute concentration to an area of high solute concentration.

4. Role in biological systems
- Diffusion pressure plays a role in the movement of gases and other small molecules across cell membranes.
- Osmotic pressure plays a role in maintaining the water balance and osmotic potential of cells.

Conclusion:

In summary, diffusion pressure and osmotic pressure are two different types of pressure that are created by the movement of molecules and water molecules, respectively. While diffusion pressure is a physical pressure that results from concentration gradients, osmotic pressure is a chemical pressure that results from the concentration of solutes. Both types of pressure play important roles in biological systems.

osmotic pressure : minimum pressure required to prevent osmosis. it is always a+ve value. also osmotic pressure is equal and opposite to solute potential. Diffusion pressure deficit : the reduction in diffusion pressure of pure water in a solution over its pure state.in the case of a plasmolysed cell , DPD= op - Tp . since Tp=0,DPD = opin the case of a turgid cell,DPD= op- Tpop=Tp,DPD = 0