AP1 Recordings 2

Diffusion and Osmosis

Diffusion

• Definition: Movement of molecules from an area of greater concentration to an area of lesser concentration through a semipermeable membrane, following the concentration gradient.

• Key Aspects:

  • Occurs both inside and outside the body.

  • Example in Everyday Life: The smell of coffee when brewed travels from the kitchen to the bedroom, illustrating diffusion as scent molecules move away from a high concentration (the pot) to lower concentration (the air).

Osmosis

• Definition: Similar to diffusion but specifically refers to the movement of water from an area of greater water concentration to an area of lesser water concentration (or greater solute concentration).

• Comparison to Diffusion: Whereas diffusion involves various molecules, osmosis strictly pertains to water molecules moving through a semipermeable membrane.

Passive Transport

• Both diffusion and osmosis are forms of passive transport, meaning they do not require ATP (adenosine triphosphate) to occur. Kinetic energy from molecular movement facilitates the process.

• Key Distinction: Passive transport does not use active transport mechanisms.

Solutions

• Definition of a Solution: A mixture composed of two parts:

  • Solute: The smaller component (e.g., salt in saline solution).

  • Solvent: The larger component (e.g., water in saline solution).

• Examples of Solutions:

  • Saline Solution: Salt dissolved in water.

  • Coffee: Coffee grounds (solute) in water (solvent).

  • Shampoo: Various cleaning agents (solute) dissolved in water (solvent).

Experiment Overview: Blood Cells in Different Solutions

• Context: Blood is essentially a saline solution with equal parts of salt and water.

  • Blood pH is approximately 7.2 to 7.4, slightly alkaline.

• Three Solution Types: The impact of different concentrations of saltwater solutions on red blood cells will be examined:

  1. Isotonic Solution: Equal concentrations of salt and water inside the cell and in the solution.

     • Outcome: No net movement of water or salt. The cell remains unchanged.

  2. Hypotonic Solution: Lower concentration of salt outside the cell, with more water (e.g., tablespoon of salt in a gallon of water).

     • Outcome: Water enters the cell causing it to swell and potentially burst (lyse) due to higher water concentration outside the cell.

  3. Hypertonic Solution: Higher concentration of salt outside the cell, with less water.

     • Outcome: Water leaves the cell, causing it to shrink (crenate), as salt moves into the cell from a region of low concentration to high concentration.

Conclusion

• Understanding diffusion, osmosis, and the concept of solutions is critical for nursing and medical practices, especially when administering IV solutions. Failing to comprehend these processes can have life-threatening consequences.