Transcript Diffusion & Osmosis

Diffusion & Osmosis
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Solvent = solute(s) + solvent
1. examine diffusion of solutes
Ex 6.3-dialysis
􀁡2. examine diffusion of the
solvent(osmosis)
• Eg.6.2
Diffusion exercise
• Diffusion exercise
• 􀁡Movement of molecules from high
concentration to low concentration(down
the concentration gradient)
• 􀁡diffusion through solid (agar plates) liquid
and gas
Factors influencing diffusion
• 􀁡Rate and temperature (increase diffusion
w/ increase temp)
• Molecular weight (increase diffusion w/
decrease MW)
• solute MW Potassium permanganate =
294.21 and Janus Green = 511.09
• Ex 6.1- Try different temperatures
Temperature and diffusion
• Ex 6.1- Prepare the 2 plates of AGAR
• Add a drop of each dye into the well.
• Place at different temperatures
• Measure the diffusion diameter of the well
at different time intervals
Osmosis experiment
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Ex 6.2
Prepare bags as instructed in the book.
Place them at the respective beakers.
Check initial wt and wt periodically to see if
osmosis has occured
Diffusion permeability of
Membranes,
• 10 ml of solution (starch + protein + NaCl
+ Na2SO4)
• test water after 1 hr for:
• Starch w/ Iodine (blue-black)
• Cl - w/ AgNO3 (milky white ppt.)
• SO4
• - w/ BaCl2 (white ppt.)
• Protein w/ Biuret (violet)
Tonicity exercise
• plant cells (Elodea leaf cells)
• Turgid􀁡hypotonic solution,􀁡water enters
cell􀁡chloroplasts are at the periphery of
thecell
Tonicity-Ex 6.4 B
Plasmolyzed
􀁡hypertonic solution
􀁡water leaves the cell
􀁡chloroplasts are at the center of the cell
TONICITY-EX 6.4 A
• animal cells (erythrocytes)
• 􀁡normal (0.85% NaCl) isotonic, no net
movement of water
• 􀁡crenated (10% NaCl)hypertonic,water
leaves
• 􀁡hemolyzed (0.45% NaCl),hypotonicwater
enters