Osmosis and Its Impact on Living Organisms

Introduction

• West Texas Winters: Cold, icy roads leading to the use of salt.
  • Salt lowers the freezing point of water.
  • Roadside plants affected negatively by salt.
• Salt and Plant Life: Not only a winter issue, but also during hurricanes.
  • Salty water from the ocean affects soil.
  • Salt can kill plants and trees post-hurricane due to osmosis.

Understanding Osmosis

• Osmosis Defined: Movement of water through a semi-permeable membrane.
  • Moves from high to low water concentration.
  • Moves towards higher solute concentration areas.
  • Passive transport, does not require energy.
• Solutes: Substances like salt or sugar dissolved in water.

Practical Example: U-tube

• U-tube Experiment: Demonstrates osmosis with a semi-permeable membrane.
  • Water levels on both sides are initially equal.
  • Adding salt to one side (B) increases solute concentration.
  • Water moves to side B, raising its water level.
  • Side B is hypertonic to side A (higher solute concentration).
  • Side A is hypotonic (lower solute concentration).

Real-World Applications

• IV Fluids in Hospitals:
  • Pure water in IV would cause red blood cells to swell and burst.
  • IV fluids are isotonic to blood plasma.
• Aquarium Example:
  • Saltwater fish in freshwater would cause water to move into the fish cells, potentially lethal.
  • Adaptations exist for fish like salmon to handle osmosis changes.

Osmosis in Plants

• Water Uptake by Roots:
  • Root hair cells have higher solute concentration than soil.
  • Water enters root hair cells, which are hypertonic to hypotonic soil.
  • Plant cell walls prevent bursting due to entering water.

Role of Pressure Potential

• Pressure in Osmosis:
  • Water potential = pressure potential + solute potential.
  • Adding solute lowers solute potential and overall water potential.
  • Exerting pressure raises pressure potential.

Turgor Pressure

• Water Potential in Potato Cores:
  • Potato cells gain water when placed in distilled water.
  • Turgor pressure builds, supporting plant structure and growth.

Conclusion

• Significance of Osmosis: Essential for the movement of water, a vital resource for life.

Final Note

• "Amoeba Sisters": Encouragement to remain curious.