Lecture on Osmosis and Its Effects

Introduction

• Discusses the impact of salt on plants, particularly during winter and hurricanes.
• Salt on roads lowers freezing point but harms roadside plants.
• Ocean water during hurricanes affects coastal plant life.

Key Concept: Osmosis

• Definition: Movement of water through a semi-permeable membrane.
• Mechanism: Water moves from high to low concentration areas.
• Solute Concentration: Water moves towards higher solute concentration.

U-Tube Experiment

• Semi-permeable membrane in the center.
• Water levels initially equal on sides A and B.
• Adding salt to Side B increases solute concentration.
• Water moves from Side A to B.
• Hypertonic: Side B (higher solute concentration).
• Hypotonic: Side A (lower solute concentration).

Real-Life Applications

IV Fluids

• IV fluids are not pure water due to osmosis.
• Pure water would cause red blood cells to swell and burst.
• Isotonic Solutions: Used to prevent cell damage.

Aquariums

• Saltwater fish in freshwater risk cell imbalance.
• Higher solute concentration in fish cells causes water influx.
• Some fish like salmon can adapt between salt and freshwater.

Osmosis in Plants

• Roots and Water Uptake: Water moves from soil to root hairs (hypertonic).
• Pressure Potential: Plant cell walls prevent bursting.

Water Potential

• Formula: Water potential = pressure potential + solute potential.
• Negative Solute Potential: Lowers total water potential.
• Positive Pressure Potential: Raises water potential.

Example: Potato Core Lab

• Potato cores in distilled water gain water due to higher solute concentration.
• Turgor pressure from water gain supports plant structures.

Conclusion

• Osmosis is crucial for water movement in organisms.
• Vital for maintaining plant structure and functions.