Bio 100L Study guide 4

Diffusion and Osmosis Study Guide Notes

Page 1

  • Diffusion Rate of Particles

    • Larger, heavier particles diffuse slower than smaller, lighter particles.

  • Elodea Cell Appearance in Solutions

    • 10% NaCl:

      • Appearance: Elodea cells will appear plasmolyzed (shrunken).

      • Solution Type: Hypertonic to Elodea cells (water moves out).

    • 0.9% NaCl (Contact lens solution):

      • Appearance: Elodea cells maintain shape, slightly inflated.

      • Solution Type: Isotonic to Elodea cells (no net water movement).

    • Distilled Water:

      • Appearance: Elodea cells become turgid (swollen).

      • Solution Type: Hypotonic to Elodea cells (water moves in).

  • Investigation with Syrup and Dialysis Tubes

    • Measured the change in mass or weight of dialysis bags filled with different solutions.

  • Effects of Solutions on Red Blood Cells (RBCs)

    • 10% NaCl:

      • Observation: Tubes appear clear with RBCs shrinking (crenated).

      • Solution Type: Hypertonic (water moves out).

    • 0.9% NaCl (Contact lens solution):

      • Observation: Tubes appear unchanged, RBCs remain intact.

      • Solution Type: Isotonic (no net water movement).

    • Distilled Water:

      • Observation: Tubes appear cloudy, RBCs bursting (hemolysis).

      • Solution Type: Hypotonic (water moves in).

Page 2

  • Substance that Diffuses in Osmosis

    • Water is the substance that diffuses during osmosis.

  • Dialysis Bag Experiment

    • The weight of the dialysis bag filled with water increased when placed in syrup solution (due to water moving out of the bag).

  • Carrot Reaction in Solutions

    • 10% NaCl:

      • Carrots become floppy and lose water.

    • Distilled Water:

      • Carrots become crisp and swell as they absorb water.

  • Weight Gain of Dialysis Bag

    • The dialysis bag gained the most weight in 100% syrup compared to 50% syrup due to a greater osmotic gradient.

  • Definitions

    • Osmosis: The diffusion of water across a selectively permeable membrane from a region of low solute concentration to high solute concentration.

    • Diffusion: The movement of particles from an area of higher concentration to an area of lower concentration.

  • Substance Added to Tubes for Text Reading

    • Added agar or a similar gel to small tubes and attempted to read printed text through it.

  • Implication of Reading Text

    • If you can read through the tubes, it means that the cells involved are permeable to the substance and allow light to pass through.

Page 3

  • Photosynthesis Reactants and Products Identification

    • Carbon Dioxide: Reactant (R)

    • Oxygen: Product (P)

    • Water: Reactant (R)

    • Glucose: Product (P)