Exercise 3: Transport and The Plasma Membrane

• Diffusion - passive movement of particles from a region of high concentration to a region of low concentration
• What is the long term effect of diffusion and osmosis wherein all the particles are evenly distributed?

  Equilibrium
• Osmosis - movement of water from a region of low solute concentration to a region of high solute concentration across a semi-permeable membrane
• Plasma membrane - a semipermeable membrane that separates the cytosol from the external environment
• What does the plasma membrane contain that allows passive diffusion of non-polar compounds?

  lipid bilayer
• What are found in the plasma membrane that facilitate the transport of ions and polar molecules?

  Proteins
• What property is exhibited in the 3-layer setup when pipetting some oil?

  self-regenerative ability
• What does the bottom layer of water represent?

  Intracellular environment
• What does the middle layer of oil represent?

  Cell membrane
• What does the top layer of alcohol represent?

  Extracellular environment
• In adding soy sauce into the setup, what property of the plasma membrane is demonstrated?

  Semi-permeability
• In the hot water bath setup, what property of the plasma membrane is observed?

  Fluidity
• What is the correlation of temperature with membrane fluidity?

  Direct
• Where is the purple pigment anthocyanin located in some plant cells?

  central vacuole
• Plasmolysis - protoplast will shrink and occupy lesser volume compared to the cell wall
• What % NaCl is isotonic to Red blood cells?

  0.9%
• In the image below, what type of tonic solution was used and enumerate the effect on the plant cells?

  Hypertonic solution; Plasmolysed

  
• If the RBCs are treated with 10% NaCl solution, what will be the effect on the cells and what type of tonic solution was used?

  Crenation; hypertonic
• What is the importance of turgidity in plants?

  Rigid cell walls for the plant to stay upright
• If a red blood cell is treated with distilled water, what would be the effect on cells and what type of tonic solution was used?

  Hemolysis; hypotonic solution