Topic 9 Passive Transport

Topic 9: Passive Transport Starter (8)

As we watch The Inner Life of a Cell, note organelles and their functions:

  • Cytoskeleton: Dynamic structure of the cell

  • Golgi apparatus: Receives and releases vesicles that can fuse with the plasma membrane

  • Nucleus: Transports messenger RNAs that translate proteins

  • Endoplasmic reticulum: Releases vesicles containing proteins and macromolecules

Observations on Gummies in Salt Solutions

Gummies were placed in solutions at 8:25 AM:

  • No salt solution: Intact, no visible change

  • Mid-level salt solution: Intact, no visible change

  • High-level salt solution: Intact, no visible change

Predictions:

  • No salt solution: Will soften by absorbing water.

  • Mid-level salt solution: Will gradually harden and dry out due to salt draining water.

  • High-level salt solution: Will quickly harden and dry out for the same reason.

Definitions

  • Solute: Substances being dissolved

  • Solvent: Substances doing the dissolving

  • Solution: Mixture of liquid

Essential Vocabulary (7)

  • Particle Concentration: Number of particles in a given area

  • Passive Diffusion: Movement of particles from high to low concentration without energy. Dynamic equilibrium occurs with no net change in concentration.

  • Facilitated Diffusion: Proteins aide diffusion, requiring some cellular energy; prevents undesirable substances from entering the cell.

  • Osmosis: Water diffuses through a semipermeable membrane from low to high solute concentration.

  • Isotonic Solution: Equal solute concentration inside and outside the cell.

  • Hypertonic Solution: Higher solute concentration outside, causing cell to shrink.

  • Hypotonic Solution: Lower solute concentration outside, causing cell to expand.

Gummy Osmosis Demo (10)

Observations from gummy demo at 9:50:

  • No salt solution: Gummy expanded

  • Mid-level salt solution: No significant change

  • High-level salt solution: Gummy shrunk

State Changes:

  • No salt: Size expanded.

  • Mid-level: No change.

  • High-level: Size decreased.

Solution Types to Gummies:

  • No salt: Hypotonic (more salt in gummy); water enters.

  • Mid-level: Isotonic (equal salt); water enters and exits at the same rate.

  • High-level: Hypertonic (more salt in solution); water exits.

Reflection Questions (15)



  1. Salt concentration of 150g water & 30g salt?Percent by mass = (Mass of solute / Mass of solution) x 10030/180 x 100 = 16.7%


  2. U-tube setup expectations?Higher glucose side draws water from lower glucose side, balancing concentrations to reach equilibrium.


  3. 10% salt solution reaction?No significant change due to isotonic conditions.


  4. 2% salt solution reaction?Membrane expands; hypotonic conditions prevail.


  5. 30% salt solution reaction?Membrane shrinks; hypertonic conditions.


  6. Does passive diffusion use energy?No, it’s driven by the concentration gradient.


  7. Particle movement in dynamic equilibrium?Yes, particles still move; equilibrium means no net change in concentration despite ongoing movement.