Osmosis Practical

• Water potential is the measure of the potential energy of water in a system, and it determines the direction of water movement.
• Solute Potential: This is always a negative value and lowers water potential as solutes are added to water.
• Pressure Potential: In plant cells, this is due to the pressure exerted by the cell wall.
• Pure Water: Has a water potential of zero, which decreases as solute is added, making water potential more negative.
• Osmosis: Movement of water molecules across a semipermeable membrane from a region of high water potential to low water potential.
• Concentration Gradient: Water moves from areas of low solute concentration (high water potential) to areas of high solute concentration (low water potential) to balance solute levels.
• Hypertonic Solution: A solution with lower water potential than the cell causes water to leave the cell, leading to plasmolysis in plant cells.
• Hypotonic Solution: Higher water potential outside the cell causes water to enter, resulting in turgor in plant cells.
• Isotonic Solution: No net movement of water, as the water potential is equal inside and outside the cell.
• Diffusion: Movement of molecules (not just water) from an area of high concentration to low concentration until equilibrium is reached.
• Active Transport: Movement of molecules against their concentration gradient, requiring energy input in the form of ATP (ex. ion pumps in cell membranes).
• Solute Concentration: Higher solute concentration in the surrounding solution lowers water potential, influencing the direction and rate of water movement.
• Temperature: Higher temperatures increase the kinetic energy of water molecules, potentially accelerating osmosis.
• Membrane Permeability: Some membranes are more permeable to water, affecting the rate of osmosis.
• • Percentage Change=(Final Mass - Initial Mass/Initial Mass​)×100