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Diffusion & Osmosis. Solvent = solute(s) + solvent 1. examine diffusion of solutes Ex 6.3-dialysis
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Diffusion & Osmosis • 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 • 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) • Turgidhypotonic solution,water enters cellchloroplasts 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